Commonly, when scanning laboratory results, a physician will look for values that are “out of range” (high or low). It is often presumed that if FT4, TSH, and FT3 are all “in the normal range,” those hormone levels won’t be… Read More ›
Reference ranges
Cognitive barriers to analyzing “normal” thyroid lab results
Here is a common moment that occurs now and then in doctor’s offices. The physician looks up from their computer screen and tells the patient, “Your thyroid function tests came back normal, so nothing is wrong with your thyroid.” That… Read More ›
Normal FT3:FT4 thyroid hormone ratios in large populations
A normal ratio of Free T3 (FT3) to Free T4 (FT4) thyroid hormones appears to be a basic principle in thyroid hormone economy when no thyroid hormone dosing and no disease interfere. In this post, I provide graphs, quotations, and… Read More ›
Biochemical bigotry: Enforcing normalized thyroid lab results
Valentine’s day is a good day to attempt to promote kindness and tolerance toward people suffering from a rather invisible health condition. Thyroid disease. What better day than today to identify and attempt to remove a medical attitude that is… Read More ›
Relational Stability, Part 2: Normality of TSH and thyroid hormones
Does the statistically-defined “normal” TSH reference range for the healthy population describe the TSH range for a healthy individual? Does having a TSH within the normal laboratory range always mean you, as an individual are biologically euthyroid? Does falling outside… Read More ›
Principles and Practical tips for Reverse T3, FT3, FT4
This post follows up on several recent posts on the topic of Reverse T3 (RT3) and our thyroid hormone conversion enzymes, the three deiodinases. Here I’m providing some practical tips about Reverse T3 testing, test interpretation, and where we should… Read More ›
Individual thyroid ranges are far narrower than lab ranges
We’ve known since at least 2002 that being within “normal range” is never good enough when it comes to thyroid hormone blood tests. An important set of four articles has taught us that each human being has an optimal range… Read More ›
The Abbott Free T3 test kit recall of 2018-2019
Recently I came across the information about the Free T3 lab test assay kit recall by Abbott Laboratories announced in late 2018. The recall was initiated in October 2018 and the FDA record was published in February 2019. The reason… Read More ›