This week (as of October 4, 2019), a thyroid patient from British Columbia posted an image of a piece of paper handed to her at a LifeLabs laboratory.
LifeLabs BC was using this paper leaflet to explain to her why “Free T3 and Free T4 will not be tested when the TSH is in reference range.”
The paper says this:
“Thyroid Protocol Changes.
- The Thyroid Protocol is being simplified
- Going from 80 diagnoses and conditions that qualified for special case to 6
- The new special list is:
YES: Diagnosis or comments on the requisition include any of the following words or phrases:
- Pituitary
- Hypothalamic
- Hypothalamus
- Secondary Hypothyroidism (MUST specify “secondary”)
- Tertiary Hypothyroidism (MUST specify “tertiary”)
- Suspected / Query (?) analytical interference (Requisition MUST indicate that the ordering practitioner has obtained approval by a laboratory physician prior to ordering)
All other diagnoses and comments do not qualify as special case.”
In this post, I’m going to show how the leaflet reveals problems in our thyroid healthcare system.
- First of all, it shows poor communication strategies.
- This information is addressed to a physician, but it is being given to a patient. A patient has no reason to celebrate the reduction of 80 conditions to 6. What if they had one of those 80 conditions now disqualified? They may reasonably suspect that the policy is being oversimplified at the expense of their health.
- It includes 5 synonyms that mean exactly the same health condition (central hypothyroidism), so it is misleading. It makes it look like there are 6 special cases, when in fact, there are 2. This is an inflated vocabulary list, not a health justification.
- It shows no respect for the struggle of treated, thyroid-disabled patients who are working with compassionate physicians to alleviate their chronic symptoms and improve their health during lifelong thyroid therapy by finding the FT3 and FT4 levels that are optimal for their disabled bodies.
- Secondly, the handout reveals the blindness of the “normal TSH” paradigm.
- The paradigm puts too much faith in the TSH hormone and its reference interval as a proxy for the appropriateness of circulating thyroid hormones. The science in the past decade shows that the HPT axis is not defined by a perfectly log-linear TSH-FT4 relationship. Being “in range” is not synonymous with euthyroidism.
- This paradigm incorrectly presumes that the outer boundaries of descriptive reference intervals for a population function as physiologically meaningful health risk thresholds for an individual.
- It presumes that reference range boundaries ought to serve as dose adjustment thresholds for individuals on thyroid treatment. This is the fallacy of making a descriptive statistical range for non-disabled populations into prescriptions and prisons for disabled individuals.
We need exceptions for ALL people whose TSH-FT4-FT3 relationships are likely to be distorted, not just people with suspected central hypothyroidism (hypothalamus or pituitary failure).
At the end, I’ll reveal an easy fix for this failed policy.
We need to listen to the new thyroid science and stop listening to “Choosing Wisely’s” penny-pinching arguments.
Note: This article was revised Jan. 21, 2023 due to a 2nd reader complaining that it was “disparaging the laboratory” (see comments below).
I’m sorry it sounded that way. It was not my intent to disparage LifeLabs staff. I hope that the main point of the title (unchanged) has been clarified. The “LifeLabs BC handout reveals thyroid testing policy failure” …
1) a failure of communication, which can elicit mistrust from patients and frustration from physicians,
2) a failure at a larger scale, since the directives are handed down to labs from people on committees.
The policy failure #2 goes far beyond LifeLabs. The handout is part of a Canada-wide and global FT3 and FT4 cancellation trend that seeks cost savings and efficiency while being ignorant of thyroid treatment guidelines and thyroid science, which I outline here.
Fortunately, long before I revised this post, within “5 months” of its implementation, LifeLabs had changed its policy, likely because it was causing patients and doctors to complain and question it
On July 7, 2020 LifeLabs published a revision of the guideline which includes 3 additional indications for FT3 and FT4 testing when TSH is normal.
Some treated hypothyroid patients in BC will be greatly relieved! “Treatment with T3” has been included as a “special case” for FT3 and FT4 testing as of mid-2020.
Why is this needed? The TSH response to T3 dosing is very different from the TSH response to endogenously-produced T3. It is also very different from the TSH response to LT4 dosing.
During T3 therapy, TSH recovery may be delayed by at least 12h after a dose of 10mcg T3 and 90 hours after a dose of 50 mcg T3. This is a drug-induced TSH-FT3 relationship distortion because TSH recovery occurs long after the FT3 / Total T3 levels have returned close to their pre-dosing baseline (See graphs by Saravanan et al, 2007 and Jonklaas et al, 2015 in our post “Free T3 peaks and valleys in T3 and NDT therapy“).
The overzealous FT4 and FT3 test cancellation campaign
This 2019 LifeLabs policy was just one local instance of a desire to limit thyroid laboratory testing across Canada and in many countries today.
The campaign called “Choosing Wisely,” richly funded by provincial governments with taxpayer money, is being used to divest taxpayers of access to FT3 and FT4 tests.
Since a campaign to persuade physicians is not very effective, they ask laboratories to enact test cancellations.
Today, according to the way Choosing Wisely Canada testing toolkits and guidelines are being worded, the only justification for testing Free T4 and Free T3 during routine hypothyroid therapy when the pituitary TSH is normal will be based on central hypothyroidism (which causes TSH hyposecretion).
Choosing Wisely materials are an overzealous misinterpretation of thyroid treatment guidelines’ emphasis on TSH normalization.
The American Thyroid Association Guidelines (Garber et al, 2012: Jonklaas et al, 2014) did not forbid FT3 or FT4 tests during the treatment of hypothyroidism.
In fact, the 2012 guidelines gently recommended FT4 testing during levothyroxine (LT4) treatment. There is no way to misinterpret this:
“Assessment of serum free T4, in addition to TSH, should be considered when monitoring L-thyroxine therapy. Grade B, BEL 1”
(Garber et al, 2012, recommendation 8)
In fact, the 2014 guidelines permitted T3 to be an additional treatment target in patients who lack endogenous thyroid function:
“In some cases, LT4 alone may fail to restore the T3 levels to a value within the reference range in patients who have undergone total thyroidectomy and thus are devoid of residual endogenous production of thyroid hormone (39,41,42). In euthyroid patients undergoing thyroidectomy and not requiring suppressive therapy, if T3 levels are chosen as one of the therapeutic targets, it is reasonable to titrate the therapy to achieve circulating levels of T3 similar to the presurgery values while maintaining the TSH value within the range of normality.”
(Jonklaas et al, 2014, section 1b)
Given the reasoning above, the ATA would permit T3 as a therapeutic target for any person who is “devoid of residual endogenous production of [T3 and T4] thyroid hormone” for any cause, including:
- being born without a thyroid, or
- complete autoimmune thyroid atrophy (my thyroid was >0.5 mL volume at age 46), or
- complete lymphocytic infiltration and fibrosis in advanced Hashimoto’s.
Even if there is no “presurgery” T3 value, the population distribution of FT3 and TT3 is narrowly focused on the middle of the reference interval in untreated healthy subjects.
The ATA’s 2012 prohibition against using T3 to diagnose untreated hypothyroidism (Garber et al, 2012, recommendation 10) does not mean that the concentration of T3 is irrelevant to symptoms or health outcomes during treatment. When the clinical implications of low or low-normal T3 levels were addressed in 2014, the authors admitted ignorance, and no recommendation was given. They did not prohibit T3 testing in 2014.
Years after the 2014 guideline was published, in 2019, Hoermann et al found that thyroidless LT4-treated patients’ symptoms were highly correlated with FT3 levels, and individuals’ symptom-free FT3 levels were found in very narrow ranges within the reference range, and were highly individualized.
It is unfair to condemn a thyroid-disabled individual to a life of perpetual suboptimal-yet-normal FT3 simply because of a refusal to measure it!
Clearly, the guidelines say something very different from Choosing Wisely:
- FT4 testing may be recommended during levothyroxine therapy,
- T3 testing is not prohibited during hypothyroid therapy and may be permitted as an additional target,
- And there is no claim in the guidelines that FT3 or FT4 testing is “unnecessary” whenever the TSH is normal during hypothyroid therapy.
Yet an overzealous cancellation policy is being used by provincial health care systems, pushed onto laboratories and doctors, and reinforced in medical schools.
5 SPECIAL CASES ARE REALLY ONLY ONE
The Life Labs handout seems to be saying to the thyroid patient, “Wow look at all those “special cases” or “diagnoses” or “conditions” you could have that would still justify an FT3 and FT4 test!”
Anyone who understands secondary hypothyroidism will note that items 1-5 are synonyms for of ONE general diagnosis of “Central Hypothyroidism.”
Central hypothyroidism, a condition of TSH hyposecretion, is caused by
- Pituitary failure (which causes…)
- Secondary hypothyroidism (also more commonly known as “central hypothyroidism” which is strangely omitted from the list),
- Hypothalamic or
- Hypothalamus failure (which constitutes the same root word with two different endings), and
- Tertiary hypothyroidism (which is essentially hypothalamic failure, which causes the pituitary to secrete less TSH per unit of FT4).
This is not a list of 5 DIAGNOSES.
It’s a list of 5 aspects of and synonyms for ONE DIAGNOSIS.
This makes the lab look bad. It denies tests because requisitions don’t have “magic words” on them, and one key magic word is missing.
To the science-informed reader of the leaflet, it makes it seem like the clinical biochemist or lab pathologist at Life Labs, or their superiors in a committee at the health care system level, didn’t realize that these all constitute one disorder now called “central hypothyroidism.”
I recommend this reading list of diagnostic policies for central hypothyroidism.
- Beck-Peccoz, P., Rodari, G., Giavoli, C., & Lania, A. (2017). Central hypothyroidism—A neglected thyroid disorder. Nature Reviews. Endocrinology, 13(10), 588–598. https://doi.org/10.1038/nrendo.2017.47
- Persani, L. (2012). Central Hypothyroidism: Pathogenic, Diagnostic, and Therapeutic Challenges. The Journal of Clinical Endocrinology & Metabolism, 97(9), 3068–3078. https://doi.org/10.1210/jc.2012-1616
- Persani, L., Brabant, G., Dattani, M., Bonomi, M., Feldt-Rasmussen, U., Fliers, E., Gruters, A., Maiter, D., Schoenmakers, N., & van Trotsenburg, A. S. P. (2018). 2018 European Thyroid Association (ETA) Guidelines on the Diagnosis and Management of Central Hypothyroidism. European Thyroid Journal, 7(5), 225–237. https://doi.org/10.1159/000491388
- Persani, L., Cangiano, B., & Bonomi, M. (2019). The diagnosis and management of central hypothyroidism in 2018. Endocrine Connections. https://doi.org/10.1530/EC-18-0515
If you look inside, you will see them talk about hypothalamic and pituitary disorders, and they explain why the “tertiary/secondary” and “pituitary/hypothalamic” distinction is now obsolete. It splits hairs unnecessarily.
The major problem, of course, is this:
The LifeLabs form fails to say “suspected central hypothyroidism.”
It also fails to acknowledge the laboratory data and diagnostic skill needed to suspect it.
Beck-Peccoz’s 2017 article, listed above, is criticizing TSH-first policies like this LifeLabs handout.
Since a normal TSH is common in central hypothyroidism, you have to test more than just TSH before central hypothyroidism can be either diagnosed or suspected! How can you suspect it if FT4 is cancelled?
DID YOU REALLY have A LIST OF 80 unique diagnoses?
The leaflet says this: “Going from 80 diagnoses and conditions that qualified for special case to 6.”
Life Labs BC, and BC healthcare leaders, we have reason to suspect that you may imagine each word in a vocabulary list is a discrete diagnosis.
Were you really making your lab technologists and lab assistants scan a list of 80 words whenever they got a requisition for FT3 and FT4?
Yes, I bet that was an inefficient use of their time and education level.
It makes it seem like patients and their doctors are being denied vital tests just so that the laboratory staff doesn’t have to scan such a long list of synonyms.
What were the 74 health conditions (or vocabulary items) omitted from their list of special cases?
Why was it decided that these 74 no longer have the potential to distort TSH secretion, if someone formerly believed they did?
Where is the justification for their removal from the list? It is not explained in this handout.
Did the human body change? Did today’s scientific understanding of TSH-distorting health conditions and medications change?
In my reading of the scientific literature, the list of TSH-distorting variables has gotten longer over the years, not shorter.
- Haugen, B. R. (2004). The Effect of Vitamin A, Retinoids and Retinoid Receptors on the Hypothalamic-Pituitary-Thyroid Axis. In P. Beck-Peccoz (Ed.), Syndromes of Hormone Resistance on the Hypothalamic-Pituitary-Thyroid Axis (pp. 149–163). Springer US. https://doi.org/10.1007/978-1-4020-7852-1_10
- Haugen, B. R. (2009). Drugs that suppress TSH or cause central hypothyroidism. Best Practice & Research. Clinical Endocrinology & Metabolism, 23(6), 793–800. https://doi.org/10.1016/j.beem.2009.08.003
A drug that can “suppress TSH” is also a drug that can make a high TSH become deceptively normal.
Consider the more recent articles:
- Benvenga, S. (2020). L-T4 Therapy in the Presence of Pharmacological Interferents. Frontiers in Endocrinology, 11, 607446. https://doi.org/10.3389/fendo.2020.607446
- Paragliola, R. M., Di Donna, V., Locantore, P., Papi, G., Pontecorvi, A., & Corsello, S. M. (2019). Factors Predicting Time to TSH Normalization and Persistence of TSH Suppression After Total Thyroidectomy for Graves’ Disease. Frontiers in Endocrinology, 10, 95. https://doi.org/10.3389/fendo.2019.00095
- Wang, J., Gao, J., Fan, Q., Li, H., & Di, Y. (2019). The Effect of Metformin on Thyroid-Associated Serum Hormone Levels and Physiological Indexes: A Meta-Analysis. Current Pharmaceutical Design, 25(30), 3257–3265. https://doi.org/10.2174/1381612825666190918162649
Can nobody at LifeLabs take the time to defend vulnerable patients, especially patients dosing both LT4 and other drugs that distort TSH, by fact-checking policy decisions?
It would require a hero capable of being a critical thinker who is skeptical of experts and committee decisions. It would require strategic searching in PubMed and medical articles with those 74 words at hand.
Were they omitted for a good enough reason? Or were they omitted because people wanted to save money and time by preventing FT4 and FT3 testing?
Everyone wants to focus on a lab test’s price tag. But no one is capable of judging how much healthcare money a $9 FT3 or $12 FT4 test could have saved, if only it had not been cancelled.
ANALYTICAL INTERFERENCE IS A DIFFERENT ISSUE
The 6th special case in which Free T3 and Free T4 testing may be permitted is “analytical interference.”
“Suspected / Query (?) analytical interference (Requisition MUST indicate that the ordering practitioner has obtained approval by a laboratory physician prior to ordering)”
(LifeLabs Handout, unrevised version)
“Unusual cases where analytical interference is suspected or the TSH result does not match the clinical situation. The requisition must indicate that the ordering doctor has obtained approval from a laboratory physician or clinical biochemist.”
(LifeLabs policy, revised version)
As you can see, the revised version is clearer and elaborated:
- This phrase has been added “… or the TSH result does not match the clinical situation.”
- Putting “must” in lowercase letters is more respectful and less likely to annoy the patient or physician reader.
This item in the list is not like the others.
“Analytical interference” is not a medical diagnosis or health condition. It is something that could be a problem with ANY lab test.
- Pre-analytical interferences are not the responsibility or fault of the laboratory. They involve factors beyond the control of the lab:
- “Generally, TSH-independent states are observed when the disorder affects primarily the thyroid gland, but there are non-thyroid conditions that can alter the interaction and confound the diagnosis, such as trophoblastic tumors, struma ovarii, and generalized resistance to thyroid hormone or selective organ resistance to thyroid hormone. Besides, there are TSH-dependent variables due to inappropriate TSH secretion or lack of secretion such as pituitary adenoma, resistance states to thyroid hormone (generalized or pituitary), psychiatric states, smoking, and malabsorption. Besides, there are physiological variables, as follows: circadian rhythm, seasonal influences, environmental influences, exercise, posture, and pregnancy.” (Caruso et al, 2021)
- Analytical interferences (sometimes called the “intra-laboratory” phase) are due to human error or procedural mistakes in laboratory handling of samples or equipment, or the fault of the assay technology itself.
According to peer-reviewed articles, analytical aspects of lab testing involve:
- the handling of blood samples, such as storage and temperature, and attributing the sample to the correct patient,
- the storage and maintenance of materials and equipment like chemical reagents and assay machines
- the manufacturer’s or local laboratory’s process used to establish a statistical population reference range, such as not excluding thyroid patients or unhealthy people when establishing FT3 or FT4 reference ranges.
- the failure of the technology to analyze the concentration properly, and
- the test’s failure to detect different types of TSH molecules (macro-TSH, or less bioactive TSH) or interfering antibodies that yield distorted FT3, FT4, or TSH values.
In this context, the LifeLabs item #6 makes it seem like a physician with only a TSH result, without a set of distorted TSH, FT3, and FT4 results in hand could have enough grounds to suspect an analytical interference.
- Question: What type of evidence and expertise would a doctor need before questioning “analytical interference” in TSH, FT3, or FT4 test result?
- Answer: The LifeLabs handout does not explain. The physician would need to be well-educated on normal vs distorted TSH-FT4-FT3 relationships and the causes of the latter that are pre-analytical vs. analytical.
Quality control is a high priority for labs. Requiring the test-ordering physician to have the prior approval of the laboratory physician is like asking a head chef to go through his kitchen looking for contaminants just because one customer got sick. Not likely to happen.
Getting the lab to approve the questioning of their own lab test is suspicious. This final “special case” permits the “laboratory physician” to have veto power over the test-ordering physician when laboratory test technologies and procedures are in question.
Why isn’t an unbiased third party carrying out the checking?
Any genuine suspicion of analytical interference would justify going to at least one different laboratory, if not two, to use their test based on different assay manufacturers. Ideally, you would test a single blood sample on several brands of assays (Roche, Abbott, and on) to see the degree to which the test results are discordant with each other.
Even more ideally, you’d get it tested by a gold-standard “liquid chromatography tandem mass spectrometry” TSH, FT4, or FT3 test.
Certain manufacturers’ FT3 and FT4 tests have problems. Certain LifeLabs branches may use the untrustworthy Abbott assay and suspicious methods of determining the FT3 reference range.
- Abbott Laboratories’ reference range normalizes lower Free T3
- The Abbott Free T3 test kit recall of 2018-2019
Test quality concerns should be carefully investigated and fixed rather than making them too difficult to question.
Is it “ANALYTICAL INTERFERENCE” or TSH paradigm interference?
This final item on the LifeLabs BC handout indirectly reveals the deeper failure of our current thyroid testing policy.
What physicians are probably observing when TSH is inconsistent with FT3 and FT4 is not in fact analytical interference, but pre-analytical and post-analytical “TSH-paradigm interference.”
The standard TSH paradigm teaches clinicians to expect that TSH will be consistent with FT3 and FT4 and even a patient’s clinical status.
In fact, age, sex, thyroid diseases, nonthyroidal diseases, thyroid peroxidase antibodies, and dosing various medications can distort TSH-FT4 hormone relationships.
This paradigm, this false expectation of alignment and consistency, will “interfere” with thyroid test interpretation.
For example, doctors who expect TSH to have perfectly log-linear behavior during thyroid therapy may be puzzled when a patient is dosing T3 and their TSH is normal while FT4 is below range. Puzzling over the inconsistency of a low TSH and low FT4, the doctors suspected either analytical interference or central hypothyroidism. Perhaps some have tried to use this reason to justify their request for FT3 and FT4 testing (or re-testing).
Extreme overconfidence in TSH will make doctors suspect the FT3 and/or FT4 test is untrustworthy and that the TSH is so “sensitive and specific” that its judgment is always “more correct” than the direct measurement of thyroid hormones!
Blind faith in TSH is maintained by physician ignorance and inexperience.
A policy that denies FT3 and FT4 whenever TSH is normal won’t let physicians gain experience with interpreting conflicting results.
This leads to physician ignorance and blind faith in TSH. It is a vicious cycle.
Because of FT4/FT3-blinding policies, physicians rarely get the chance to observe TSH misbehavior when TSH is normal.
It is futile to judge a TSH, or an FT4 or a FT3 on the basis of whether each analyte in isolation from the other is normal, high, or low. Most results will be within or close to the reference interval, which gives a sense of false assurance to the uninformed physician that “everything is fine.” The opposite may be true if you look at hormone relationships.
During thyroid treatment, whenever values are within or close to the reference range, no single analyte in isolation has diagnostic veto power. For example, a low-normal TSH may occur when FT4 is low or undetectable and T3 dosing makes FT3 from high-normal to high. Is the patient hypothyroid due to their low FT4, or hyperthyroid for the hours when their FT3 is high?
Whenever TSH is responding to abnormal FT3:FT4 ratios induced by thyroid diseases and their therapies, TSH is not a proxy or predictor of the precise position of the other two hormones.
Fortunately, both FT3 and FT4 have the diagnostic power to reveal that a TSH level is inappropriate:
- An inappropriate TSH-FT4 relationship, even if TSH is normal or both are “normal,” has diagnostic power to suspect inappropriate TSH secretion or to suspect an abnormal FT3.
- A TSH-FT4-FT3 relationship has the strongest diagnostic power, even if all three values are within the reference interval but are inappropriately configured.
Many doctors are utterly ignorant of the larger potential for distorted TSH-FT4-FT3 relationships during thyroid diseases and their therapy. They have no clue that a patient with Hashimoto’s can also acquire pituitary failure, or that a low titer of Graves’ disease antibodies may interfere with therapy. All they are trained for is how to diagnose thyroid conditions in isolated and simple cases BEFORE thyroid therapy distorts the hormone relationships in a different direction.
Doctors will never learn how to interpret abnormal TSH-FT4-FT3 relationships if they rarely see a full set. When all three are normal, or only one is abnormal, and if they lack training, they won’t be able to “see”
- Central hypothyroidism within the normal reference ranges of TSH and FT4,
- a T3-secreting nodule when TSH is normal,
- a TSH-secreting adenoma when TSH is normal but ought to be low
- a TSH distortion caused by advanced age
- a TSH distortion caused by inflammatory cytokines or hypoxia during severe illness
- a TSH distortion caused by Graves’ disease or TSH-receptor-blocking antibodies
- and so on
Physicians should be learning how to interpret TSH-FT4-FT3 relationships by experience over the years.
DIAGNOSE THE POLICY FAILURE
We need to observe TSH inconsistency with FT3 and FT4 and clinical presentation.
Collecting the inconsistent data is necessary to correctly diagnose not only the laboratory test quality and the patient’s thyroid hormone status. But first, we have to diagnose this deeper issue …
The critical FAILURE of this TSH-centric thyroid testing policy in the context of thyroid therapy.
- You can’t observe the failure of TSH-only testing by repeatedly testing only the TSH!
Our most popular blog post shows patients how to use science to adjust their own TSH results: “7 ways to raise TSH without reducing thyroid dose.”
Consider all the ways in which normalized TSH fails to give enough information to guide effective thyroid therapy:
- Individual thyroid ranges are 38-68% the size of the lab reference range
- Targeting TSH? It’s not as specific or as sensitive as people claim.
- TSH “can be very misleading” during thyroid therapy, say researchers
- The TSAb stimulating antibody can lower TSH despite euthyroid status.
- In Winter, everyone gains T3 except thyroidless patients on LT4 therapy
- The TSH-T3 disjoint in thyroid therapy
- Gullo: LT4 monotherapy and thyroid loss invert FT3 and FT4 per unit of TSH
Consider the years of suffering these test-cancellation policies cause thyroid patients whose TSH does not reflect their hypothyroid symptoms during treatment, whose physicians refuse a dose increase or T3 treatment “because the TSH is normal.”
A QUICK FIX FOR THE POLICY FAILURE
How many citizens in your healthcare region are on lifelong thyroid hormone replacement at doses higher than 88 mcg/day? A very small percentage of your population.
The lifelong health and welfare of vulnerable thyroid patients is worth a few dollars extra per test.
For thyroid patients who are symptomatic on levothyroxine (LT4) despite a normal TSH, there is no reason why they should not obtain FT3 and FT4 tests, since their TSH-FT3 relationship will be abnormal and their FT3:FT4 ratio will usually be low. Testing just our TSH is not going to provide enough information about how normal their FT3 and FT4 are.
For thyroid patients on T3-inclusive thyroid medication, FT3 and FT4 should be the norm, and the FT3 should be tested >12h post-dose, during the 2nd “slow clearance” phase. Testing just our TSH is not going to provide enough information.
Add a couple of checklist items to the laboratory requisition:
“X = On levothyroxine (LT4) thyroid hormone replacement > 50 mcg/day.”
“X = On liothyronine (LT3) or desiccated thyroid (test >12h post-dose)”
“X = Other clinical indications, i.e. suspected central hypothyroidism.”
This should cover all the necessary, valid conditions for FT3 and FT4 testing.
- Now there’s no need for vocabulary lists for exceptions to rules.
- Now you can give the doctor experience, which will develop their clinical judgment.
- Now you can prevent unnecessary conflict between doctors, patients, and laboratories.
- Now you don’t have to discipline doctors or send them for brainwashing sessions to be re-indoctrinated in the TSH paradigm whenever they continue to order FT3 and FT4 tests.
Instead, you can implement algorithms like SPINA-Thyr in your lab reports to help doctors see even mild subclinical cases of central hypothyroidism before they get worse. We see central hypothyroidism causing thyroid hormone underdose in patients undergoing treatment for primary thyroid failure, and that is why we have a post about “Screening for central hypothyroidism during thyroid therapy.”
You can advocate for workshops that help physicians make better use of FT4 and FT3 lab data, such as
- interpreting a normal TSH in the context of abnormal TSH-FT4-FT3 relationships
- how hormone relationships shift from before therapy to during thyroid disease and therapy.
- how to adjust FT3 and FT4 levels to optimize thyroid patients’ therapy to the individual.
– Tania S. Smith
I work for Lifelabs and I’m a bit thrown back at how you are blaming us phlebotomists for following MSP guidelines. I have Hashimoto’s and completely disagree with their “new” protocol, but I can tell you we aren’t making the rules. And yes, we did follow the 80 diagnoses before. But your doctor had to write it on the req, most of the time they leave it blank which means no special case. MSP makes the rules, not Lifelabs.
Dear Crystal, thanks for chiming in. So sorry to have offended you. I did not intend to blame the innocent and hard working phlebotomists like you, of course. The problem is much larger than any single staff member at LifeLabs, as I do explain in my article: The policies come from penny-pinching campaigns and outdated 2012 and 2014 thyroid clinical guidelines, and “These policies are then implemented by provincial health care systems, pushed onto laboratories and doctors and reinforced in medical schools.”
Such handouts to patients seem like an insult to the intelligence (and thyroid health) of all phlebotomists, patients and doctors who have a scientific knowledge of thyroid hormones and the HPT axis.
The wording and medical logic of the “LifeLabs” patient handout seems to be written by a LifeLabs manager. It seems to be a sloppy interpretation and elaboration of public health care documents. This is the closest I can find in the BC Medical Services Plan, as it has the laboratory flowcharts on pages 4 and 12 https://www2.gov.bc.ca/assets/gov/health/practitioner-pro/bc-guidelines/thyroid-function-testing.pdf
Other labs do not use this wording found in the leaflet given to the patient. I cannot find this exact “vocabulary list” or its policy wording anywhere in MSP. If you can find it, please send the link.
Alternatively, perhaps it is in some secret unpublished memo, but it should not be unpublished if health policy is truly public.
What do you really think of the errors in the leaflet? In addition to mistakenly implying these are mutually exclusive diagnoses when they are like a thesaurus entry, don’t you think it is very odd that the LifeLabs document omits the most general term of “central hypothyroidism” from the list, which would cover FIVE of the listed terms? In addition, the leaflet also misinterprets page 12 of this pdf, which clearly says it is not “Query analytical interference” that requires consultation with laboratory physician. In the BC MSP file, such a “consultation” is clearly connected to the cross footnote symbol on “Previous TSH inconsistent with patient presentation.” Finally, the communication on a slap-dash photocopied leaflet to a patient is also delivered without sufficient context, authority, contact & appeal information, or citations.
I am truly shocked that, as you attest, it is true that a list of 80 words or conditions was used previously — it seems so inefficient. My guess is that it was a list inflated by synonyms like the present list, and the list may have included many non-thyroidal illnesses like diabetes, heart failure, depression, cardiac surgery, kidney failure, and myriad other diseases that can cause life- and health-threatening alterations in TSH, FT4 and FT3.
If these other conditions like “heart failure” were removed from eligibility for a FT3 or FT4 test that might save their life, then people with such conditions should be upset too, not just thyroid patients.
But back to the present testing crisis being faced by thyroid patients and their good doctors.
Yes you are right, more doctors ought to be aware of the magic words they must write in the blanks of a requisition, especially now that the wording has been so sadly narrowed by the narrow-minded policy writers.
I will write a new post to advise patients and doctors of ways to get tested even in the presence of the new “special case” policy, and perhaps some of them will work.
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Just came upon this article as a colleague mentioned it in passing to me today (we both work in laboratory medicine). While I understand the poor optics gained from a more informed patient dissecting LifeLabs form, this article is full of misconceptions, misinformation and accusations based on zero evidence. The way in which you have described your understanding of laboratory medicine clearly demonstrates the fallacy of crafting arguments based on a few Google searches. Have you spoken to anyone who actually works in LifeLabs or any clinical laboratory for that matter? My guess is no. I respect that the perspective you are taking is to advocate for patients but disparaging the laboratory based on assumptions and some online facts takes away any credibility for you as reliable source of laboratory testing information.
Dear Rob, I think you can be happy about getting my attention. Since you posted your comment, I have consulted with a fellow thyroid patient who has 20+ years of experience working in middle management in diagnostic laboratories.
I have revised the post to clarify what I meant to say– the handout makes it LOOK like lab staff are uneducated and clueless about the science.
I’m sorry if you felt the post was “disparaging the laboratory,” but you will now see that the post is putting the blame on systemic scientific ignorance that goes beyond a single laboratory company. You can see that I have replied to a previous commenter who was also unable to see past their self-defensiveness and understand what I was really attacking — a systemic policy failure. Handouts like these make lab staff really LOOK uneducated and unable to fact-check policies handed down to them from above.
Please, if you are an educated laboratory technologist or pathologist or clinical biochemist, you can be a whistleblower or talk to admins about the narrowness of such a policy.
The title stays the same — because the handout truly “reveals” a widespread policy failure at every lab that would dare to have such a narrow policy. — And I’ve added the information about the enhancement of their policy that occurred within months.
And by the way, I have taught rhetoric at a university for 20+years. If you were my student, I would have to say that your comment has engaged in a far more debased form of public rhetoric than the unedited post you critiqued. I see the ad hominem fallacy, and failure to provide relevant evidence when engaging in a refutation. You certainly did not need to engage in disparaging my research process (as if I engage in superficial googling). You could have provided evidence from an authoritative published source (not by superficial googling) wherever you think there is an error, instead of blaming the post to be based on “zero evidence.”
I suggest you could read any of the articles and links — many were provided in the original post.
Dear Tania,
I am only going to address the section “ANALYTICAL INTERFERENCE IS A DIFFERENT ISSUE” as that relates to my profession. Although your intention is to point out a systemic policy failure, the rhetoric in this section not only casts doubt on the quality of clinical laboratories but also, brings up irrelevant points to support an overall message that laboratories do not know what they are doing.
1) The points laid out in the “technical aspects” are true, but what is the relevance here to interferences in thyroid tests other than to elicit doubt in readers that laboratories are managing every step of the testing process well? It is well-known that interferences in thyroid tests mainly revolve around interfering antibodies – this is well supported in literature and published case studies.
2) “Getting the lab to approve the questioning of their own lab test is ridiculous.” What exactly is ridiculous for laboratories to engage in continuous quality improvement, which encompasses being vigilant about our own tests and its limitations? Of course, in the way you have led up to this phrase (without appropriate context and information) the reader will likely agree with this statement. Again, you have reached this conclusion without really any credible knowledge of the inner workings and quality management of a laboratory.
3) The most problematic statement in this section is your description of the “untrustworthy” Abbott assay. What exactly is this statement based on? I hope it is not the singular referenced reagent recall for Abbott’s FT3 which is now being generalized to all the Abbott thyroid assays.
Again, it is not clear where you have received your information on these behind-the-scenes processes that occur in clinical laboratory but my impression, is that you have not spoken to the correct individuals to be able to reach these conclusions. Great that you spoke to a fellow thyroid patient with middle management experience but that is a vague description (some management staff have no exposure or experience with scientific aspects of testing) and still is not sufficient to confirm all these conclusions in your posts. I apologize for the comment on “Googling” but still, I do not see a true and accurate representation of lab testing given with relevant context.
Dear Rob Wong, Reply 2. You complained, “you have not spoken to the correct individuals to be able to reach these conclusions.” You also appear to believe that my consultation of a lab professional was an effort to supply some sort of evidence for my conclusions, when that is not why I consulted them. I do not need to speak to an expert to reach valid conclusions when I can do better: I consult relevant scientific journal articles on the topic.
I am sorry to have to point out that this reveals your belief in the fallacy of authority. This fallacy is a common crutch and handicap in medical discourse. See the article about this fallacy by Cline on ThoughtCo https://www.thoughtco.com/logical-fallacies-appeal-to-authority-250336
Authority, even field-relevant authority, is never a sufficient basis for conclusions about the validity of a medical policy. Nobody should come to conclusions about a medical policy merely by speaking to people with relevant medical credentials. Even complete consensus among many experts is not a sufficient basis for evaluating a policy.
Every medical claim, and every medical policy, should be based on high-quality scientific evidence found in experiments published in peer reviewed articles. That’s where I go to get my evidence.
Of course, relevant and solid credentials can strengthen the persuasiveness of evidence-based rational argumentation. But claims plus credentials can’t stand on their own to establish the truth or power of those claims. This is a fundamental principle of rhetoric and logic. It applies to every field, not just medicine.
When judging the truth or reasonability of a medical claim, we should try to avoid being biased by the credentials of the person who makes the claim — a patient like me, a researcher, physician, or a laboratory pathologist. The quality of evidence plus reasoning that establishes a claim should overpower the mere credentials of the person who makes a claim.
Experts’ opinions can be wrong when they misjudge the strength of the evidence supporting their opinion and are ignorant of the evidence that weakens their opinion, and/or when they use fallacious logic to support their opinions. Non-experts’ arguments can be right, fair and reasonable when they do not fall into these intellectual traps.
In fact, basing an argument’s conclusions on the opinions of experts is just as weak as using an isolated TSH result to make a claim about a person’s thyroid status, pituitary status, and circulating thyroid hormone supply without having an FT4 and FT3 result to verify the appropriateness of their TSH. Why should we be told to rely only on the pituitary’s response when the best way to verify the integrity of the pituitary response is by looking at the thyroid hormone concentrations?
The scientific literature that I can cite, when asked, or when needed, provides a huge pile of verifiable evidence and reasoning. It has more collective authority than my non-medical credentials, your medical credentials, and the credentials of the most eminent laboratory scientist you can name.
However, as I read scientific journal articles, I don’t just absorb what authors say without question while trusting in their credentials. I engage in active critical analysis of the basis of their medical reasoning by looking at their data tables, graphs, methods, and even by going to some of their references.
When we handle scientific evidence, the strength of our arguments is not located in our credentials and the credentials of those we cite. It is demonstrated by our methods: how intelligently and responsibly we select and interpret evidence, evaluate it, and use it ethically and reasonably to promote human health and a more accurate understanding of human physiology.
Therefore, if you have any questions about one of the many reasons why a normal TSH result does not function as an infallible proxy for an acceptable and safe FT4 and FT3 supply, then please ask me for my peer-reviewed research citations and references. I’m happy to strengthen the arguments of this article by peppering it with additional hyperlinked citations and reasoning about what those sources say.
– Tania S. Smith
Dear Rob, thanks for your reply. I have two responses. Reply 1. I think it’s very unfortunate that you’re still under the mistaken impression that I’m attacking laboratories. You and I ought to be on the same side, defending the real victims.
The real victims are patients with a normal TSH who do not have appropriate thyroid hormone levels that defend their health and safety, but their FT3 and FT4 tests are cancelled.
Why am I expressing frustration and anger against LifeLabs if I claim that they are not my enemy and I’m not attacking them? Imagine a contemporary superhero film, and clinical laboratory professionals are the potential superheroes. Some films begin with a disillusioned or apathetic superhero that seems to be ignorant of, or even complicit in, the attacks of evil villains on vulnerable people. The plot usually involves representatives of those victims calling out to the superhero to rouse them to their duty to defend the victims from harm.
That’s me. I’m calling on you and your colleagues to defend us. How is it an attack on laboratories to call on them to perform to their highest standards and values? By being angry with LifeLabs, and calling on them to come to their senses, I am revealing thyroid patients’ dependence on laboratories as our defenders.
Did my anger last when LifeLabs changed their policy? No. I praised them for doing so. I am pleased that they showed they are willing to make more reasonable exceptions to the TSH-first testing flowchart.
You asked “what is the relevance here to interferences in thyroid tests other than to elicit doubt in readers that laboratories are managing every step of the testing process well?”
Why would the existence of assay analytical interferences undermine public trust in laboratories? Given that assay interferences do exist, we need the services of biochemical lab experts to defend us from them! Assays are fallible technologies, but I’m thankful that the expertise and quality control measures of laboratory professionals can control and reduce their fallibility and often advise clinicians on their interpretation.
By pointing to the fallibility of assays, I am trying to tear down the idol of unreasonable TSH-worship, not tear down trust in biochemical labs in general.
We need critical-thinking lab pathologists. We need more human vigilance regarding the fallibility of assays, especially one which has such a controversial reference interval as TSH.
Those who place blind faith in TSH and its reference interval ought to become more aware of which interferences do, and do not, interfere with the TSH assay that has become such a huge barrier to thyroid hormone testing.
A laboratory professional should know that TSH results can be compromised by much more than just anti-Streptavidin antibodies, monoclonal gammopathies, and biotin. (Ghazal et al, 2022, “Hormone Immunoassay Interference: A 2021 update”) Too many additional factors make TSH assays unsuited to play the role of the gatekeeper test that cancels a FT3 or FT4 test.
If you are a laboratory professional aware of these analytical interferences, your heightened awareness of assay fallibility in general should sensitize you also to the pre-analytical and post-analytical interferences that undermine a TSH-worshipping policy.
No matter how carefully you control for TSH laboratory interference within laboratory walls, you have no superpowers to make TSH results infallible enough to justify the way they’re being misused and misinterpreted.
First, we cannot make an immunoassay into a TSH bioassay, but scientists tell us that only a bioassay can measure the cAMP that is produced in cells by TSH receptor signaling to determine the relative potency of the various TSH isoforms in circulation. Why should the mere quantity of the TSH hormone concentration matter more than its variable biological potency? Next, we cannot make two TSH assays invulnerable to inter-assay variability around the upper limit of their reference intervals. Further, no one can make a single TSH measurement represent the 24-hour mean TSH in that individual, since the time of day of the blood draw will manipulate the test result to an unpredictable degree based on the individualized, variable width of circadian TSH rhythms. Moreover, no one can deny the fact that TSH interpretation by a population reference interval has major problems due to its low “index of individuality.” And that is not the end of the list of uncertainties surrounding any normal or abnormal TSH result in isolation from the most abundant (FT4), and most potent (FT3), thyroid hormones.
Laboratory staff themselves, who ought to know better, are not immune to TSH idolatry, so they need whistleblowers among patients, and within their ranks. It’s unjust to defend a tyrant by saying his opinion is natural law because he is rich and powerful and has many friends, and to silence dissent by killing protesters against his regime. It’s an equally unjust mechanism that defends the infallibility of the TSH result because the TSH policy has many powerful advocates and it’s cheaper. Of course, advocates of TSH-only testing want us to silence and cancel the FT3 and FT4 tests that ought to be used to contextualize and interrogate the validity of the TSH result.
As a laboratory professional, you have one socially-based superpower I lack as a mere patient who advocates for patients. You have the institutional position and power to speak back to policymakers who want to institute such flawed policies.
I’m supplying you with more evidence for an argument you can make on behalf of vulnerable patients and better thyroid science, if you are willing to take a stand.