For more than 3 years my tsh levels have been hovering around or below the bottom of the range. My doctors have used this for refusing to increase my dose of levo.
The test from my gp just before Christmas was 4.11 (0.34-5.44) and I repeated the test with Monitor my Health last month which recorded 3.33 (0.27-4.2) My T4 was 17.7 (12-22) and T3 was 3.7 (3.1-6.8). When tested my T4 and T3 have always remained remarkably constant and did not change last month when my TSH shot up.
Can anyone shed any light on this change please?
Written by
mill44
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The link between TSH, FT4 and FT3 in hyperthyroidism is very different from taking thyroid hormone (T4) in therapy. In hyperthyroidism, FT4 and FT3 are usually well above range and TSH is very low or undetectable. In therapy, FT4 can be high-normal or just above normal, TSH can be suppressed but FT3 (the important hormone that controls your health) will usually be in the normal range. FT4 and TSH are of little use in controlling therapy and FT3 is the defining measure. A recent paper has shown this graphically:
Heterogenous Biochemical Expression of Hormone Activity in Subclinical/Overt Hyperthyroidism and Exogenous Thyrotoxicosis
February 2020 Journal of Clinical and Translational Endocrinology 19:100219
DOI: 10.1016/j.jcte.2020.100219
LicenseCC BY-NC-ND 4.0
Rudolf Hoermann, John Edward M Midgley, Rolf Larisch, Johannes W. Dietrich
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