%0 Journal Article
%T Low Reverse T3: A Reliable, Sensitive and Specific in Diagnosis of Central Hypothyroidism*
%A Sarah Exley
%A Sonal Banzal
%A Udaya Kabadi
%J Open Journal of Endocrine and Metabolic Diseases
%P 137-143
%@ 2165-7432
%D 2021
%I Scientific Research Publishing
%R 10.4236/ojemd.2021.117011
%X Background: Low free T4 and normal/low TSH concentrations are often noted in clinical practice and denote presence of ”°Euthyroid Sick Syndrome”± or Central Hypothyroidism. However, accurate diagnosis is difficult even with determination of free T3 being low/normal in both. Repeated determination of these tests may help differentiate between these disorders. Objective: Evaluation of reverse T3 to differentiate between ”°Euthyroid Sick Syndrome”± and Central Hypothyroidism. Subjects and Methods: Free T3 and Reverse T3 were determined as ”°add on”± tests using previously drawn blood samples of 78 consecutive adults showing low free T4, 0.80 ”Ą 0.02 and low/normal TSH, 1.29 ”Ą 0.40 [normal ranges, 0.89 - 1.70 mcg/dl; 0.45 - 4.67 uU/ml]. Free T4, free T3, TSH and reverse T3 levels were also determined in age-matched 35 healthy volunteers and reassessed in study group. Statistical analyses for comparisons were conducted between groups. All data are reported as Mean ”Ą SEM. Results: Reverse T3 established two distinct groups: 1) subnormal concentrations, 8.31 ”Ą 0.52 [range, 11 - 14 ng/dl]; 2) supernormal levels; 32 ”Ą 4 [normal Range 12 - 26]. Free T3 concentrations were subnormal or normal, 1.6 - 2.9 [normal range, 2.3 - 4.2 ng/ml] in individuals amongst both groups. On reassessment after 3 - 6 weeks, free T4, free T3, TSH and reverse T3 normalized in group with normal or elevated reverse T3 indicating recovery from ”°Euthyroid Sick Syndrome”± whereas free T4 and reverse T3 remained subnormal in the other group suggesting presence of Central Hypothyroidism. Conclusion: Reverse T3 is a reliable laboratory test differentiating between Central Hypothyroidism and ”°Euthyroid Sick Syndrome”± in subjects with low free T4 and low/normal TSH levels.
%K Euthyroid Sick Syndrome
%K Central Hypothyroidism
%K Reverse T3
%K Free T4
%K Free T3
%K TSH
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=110736