Regulator recommends thyroid function tests for patients on levothyroxine with persistent symptoms

2021 ◽  
Keyword(s):  
Thyroid Function ◽  
Thyroid Function Tests ◽  
Persistent Symptoms ◽  
Function Tests

scholarly journals THERAPY OF ENDOCRINE DISEASE: T4 + T3 combination therapy: is there a true effect?

2017 ◽  
Vol 177 (6) ◽  
pp. R287-R296 ◽  
Author(s):  
Wilmar M Wiersinga
Keyword(s):  
Combination Therapy ◽  
Thyroid Function ◽  
Healthy Subjects ◽  
Randomized Clinical Trials ◽  
Peripheral Tissue ◽  
Thyroid Function Tests ◽  
Peripheral Tissues ◽  
Persistent Symptoms ◽  
Function Tests ◽  
Number Of Patients

About 5%–10% of hypothyroid patients on T4 replacement therapy have persistent symptoms, despite normal TSH levels. It was hoped that T4 + T3 combination therapy might provide better outcomes, but that was not observed according to a meta-analysis of 11 randomized clinical trials comparing T4 monotherapy with T4 + T3 combination therapy. However, the issue is still subject of much research because normal thyroid function tests in serum may not necessarily indicate an euthyroid state in all peripheral tissues. This review evaluates recent developments in the field of T4 + T3 combination therapy. T4 monotherapy is associated with higher serum FT4 levels than in healthy subjects, and subnormal serum FT3 and FT3/FT4 ratios are observed in about 15% and 30% respectively. T4 + T3 combination therapy may mimic more closely thyroid function tests of healthy subjects, but it has not been demonstrated that relatively low serum FT3 or FT3/FT4 ratios are linked to persistent symptoms. One study reports polymorphism Thr92Ala in DIO2 is related to lower serum FT3 levels after thyroidectomy, and that the D2-Ala mutant reduces T4 to T3 conversion in cell cultures. Peripheral tissue function tests such as serum cholesterol reflect thyroid hormone action in target tissues. Using such biochemical markers, patients who had a normal serum TSH during postoperative T4 monotherapy, were mildly hypothyroid, whereas those with a TSH 0.03–≤0.3 mU/L were closest to euthyroidism. Peripheral tissue function tests suggest euthyroidism more often in patients randomized to T4 + T3 rather than that to T4. Preference for T4 + T3 combination over T4 monotherapy was dose-dependently related to the presence of two polymorphisms in MCT10 and DIO2 in one small study. It is not known if persistent symptoms during T4 monotherapy disappear by switching to T4 + T3 combination therapy. The number of patients on T4 + T3 therapy has multiplied in the last decade, likely induced by indiscriminate statements on the internet. Patients are sometimes not just asking but rather demanding this treatment modality. It creates tensions between patients and physicians. Only continued research will answer the question whether or not T4 + T3 combination therapy has true benefits in some patients.

In a bind: abnormal thyroid function tests

2019 ◽  
Author(s):  
Catriona Hilton ◽  
Farhan Ahmed ◽  
Asif Ali
Keyword(s):  
Thyroid Function ◽  
Thyroid Function Tests ◽  
Function Tests

scholarly journals Falsely diagnosed thyrotoxicosis caused by anti-streptavidin antibodies and pre-wash procedures

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Takuya Ishikawa ◽  
Hiroyuki Sakai ◽  
Tokutaro Itaya ◽  
Suwanai Hirotsugu ◽  
Jumpei Shikuma ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Magnetic Particle ◽  
Thyroid Function Tests ◽  
Case Presentation ◽  
Analytical Interference ◽  
Function Tests ◽  
Inappropriate Treatment ◽  
Published Report ◽  
Old Japanese ◽  
Polyethylene Glycol Precipitation

Abstract Background Anti-streptavidin antibodies are causal determinants of analytical interference during Thyroid function tests, and numerous reports have detailed such interference, with anti-streptavidin antibodies attracting attention. Case presentation We conducted a straightforward investigation of interference due to anti-streptavidin antibodies, with a case of a 60-year-old Japanese man who consulted our department for inconsistencies between his clinical course and Thyroid function tests. Experiments were conducted using Cobas8000 e602, which employs assay procedures with pre-wash to evaluate FT4 and FT3 levels. Conclusions To our knowledge, this is the first published report to clearly investigate such interferences using a combination of polyethylene glycol precipitation, heterophilic blocking tube precipitation, streptavidin-coated magnetic particle precipitation, and different instruments with or without pre-wash. Clinicians should consider that interferences caused by anti-streptavidin antibodies could lead to a misdiagnosis of thyrotoxicosis. Moreover, discussions between laboratory specialists, clinicians, and manufacturers are required to identify interferences and avoid unnecessary examinations and inappropriate treatment.

Sign in / Sign up

Export Citation Format

Share Document