Reference ranges

• Thyrotoxicosis can occur with high or normal TSH?

  Table 17.1 in Braverman & Cooper’s 2013 chapter in Werner & Ingbar’s The Thyroid textbook, 10th edition, lists many causes of thyrotoxicosis. The only time the TSH _hormone_ is listed as a cause of thyrotoxicosis is in the case of “Inappropriate TSH hypersecretion.” If thyrotoxicosis can occur when TSH is inappropriately _high_ or non-suppressed in…

  thyroidpatientsca

  July 4, 2019

  Reference ranges, Testing policy, Thyrotoxicosis, TSH test

• Thyrotoxicosis? Many factors can lower TSH

  Many substances and health factors can, independently of thyroid hormones, lower TSH secretion significantly. These factors are not listed in Braverman & Cooper’s chapter on thyrotoxicosis in Werner & Ingbar’s The Thyroid textbook, 10th edition 2013, because their chapter avoids defining the syndrome by a low TSH. Nevertheless, these TSH-lowering factors should always be mentioned…

  thyroidpatientsca

  July 2, 2019

  Central hypo, Diet & Nutrition, Genetics, Hypothalamus, Pituitary gland, Reference ranges, Research Reviews, Thyrotoxicosis, TSH hormone, TSHR-Antibody

• Abbott Laboratories’ reference range normalizes lower Free T3

  In late 2018, in Ontario, Life Labs changed its reference range for Free T3 (Triiodothyronine) thyroid lab tests. In our closed Canadian Thyroid Support Group where patients share their lab results and therapy progress over time, this particular Free T3 test has been behaving strangely so far, especially comparing changes from the old assay to the…

  thyroidpatientsca

  January 6, 2019

  Free T3 test, Reference ranges, Test quality control

• Interpreting Free T3 and Free T4 in therapy

  

  Hypothyroidism is a thyroid hormone insufficiency, so it’s only logical to measure the success of therapy by the goal: T4 and T3 thyroid hormone sufficiency. Especially T3 sufficiency, the active hormone. Lab tests like Free T3 and Free T4 can indicate “relative” T3 and T4 sufficiency in bloodstream … but one has to carefully interpret…

  thyroidpatientsca

  July 28, 2018

  Free T3 test, Free T4 test, FT3:FT4 ratio, Reference ranges, Therapy paradigms

• Fear of Low TSH causing osteoporosis

  Image based on Figure 4 in this source: Gogakos, A. I., Duncan Bassett, J. H., & Williams, G. R. (2010). Thyroid and bone. Archives of Biochemistry and Biophysics, 503(1), 129–136. https://doi.org/10.1016/j.abb.2010.06.021 Dear Doctors, You may experience this scenario with some of your thyroid patients. Your patient’s TSH is near the bottom of reference range, but…

  July 19, 2018

  Biomarkers, Bones, Reference ranges, TSH hormone, TSH test