Are we using Thyroid Function Tests Appropriately?

Thyroid function tests are very important for the diagnosis and monitoring of patients with thyroid dysfunction. The guidelines recommend serum thyroid stimulating hormone (TSH) as the single most reliable test to diagnose all common forms of hypothyroidism and hyperthyroidism. The aim of this study was to analyze the ordering pattern for thyroid function tests by physicians and the analysis of results based on the clinical history. The mean age of the patients was 32.5 ± 6.5 years. Majority of samples (87.7% of total) were received from the departments of Medicine and Gynae. Thyroid profiles (47.5%) were ordered more frequently as compared to TSH only (46%). There was no significant difference in the percentage of normal reports for both types of tests. 77.8% of TFT and 76.6% of TSH samples had results within the reference range. The percentage of abnormal results was 13.7% in the patients who were screened for thyroid disorders. There is a need to redefine the case definition for thyroid dysfunction and order the appropriate test in a rational and cost effective manner.     

甲亢与甲减患者血清MDA水平的测定

为了探讨甲亢、甲减患者细胞损伤程度的变化,本文应用放射免疫方法(RIA)对甲亢、甲减患者与正常人血清进行了甲状腺功能的测定,同时用改良TBA微量法测定三组血清丙二醛(MDA)含量的变化,进一步进行其相关性分析。结果显示;甲亢组MDA水平显著高于正常对照组(P<0.01),甲减组MDA水平与正常对照组无显著性差异(P>0.05),甲亢组血清MDA水平显著高于甲减组(P<0.01);但是MDA含量与T3、T4水平无相关性(r=0.085,P>0.05;r=0.076,P>0.05)。提示甲亢患者MDA水平的变化,可能是由于细胞代谢增强导致的细胞损伤引起。     

Serum creatine phosphokinase in thyroid disorders

The decreased serum levels of triiodothyroinine (T3) and thyroxine (T4) in hypothyroid patients is well established but whether there is any correlation of creatinephosphokinase (CPK) with hypothyroidism is not well established. There is a paucity of reference on this study. Therefore a study of serum CPK and thyroid profile was carried out in thyroid diseases. In hypothyroid patients T3, T4 levels in serum were found to be lowered with an increase level of thyroid stimulating hormone (TSH) associated with marked rise in serum CPK level. In hyperthyroid patients serum levels of T3, T4 were found to be increased with decrease in TSh with significant decrease in creatine phosphokinase level. Serum creatine phosphokinase levels thus show an inverse relation with serum T3, T4 levels.     

Thyroid Disorders in Patients of Type 2 Diabetes Mellitus

The study was planned to assess the prevalence of thyroid disorders in type 2 diabetes in North Indian population and to correlate the serum insulin and glycosylated haemoglobin levels with thyroid hormones. It is a case control study. One hundred and twenty patients of type 2 diabetes were included in the study along with 117 adults of the same age group and normal glucose levels as controls. All blood samples were taken from subjects who fasted for at least 12 h before the blood collection. Glycosylated hemoglobin was determined by ion exchange chromatography and serum insulin and thyroid hormones were assessed through enzyme linked immunosorbent assay. Fasting blood glucose and glycosylated haemoglobin levels were significantly higher in diabetics showing a poor glucose control. Serum tri-iodothyronine values were significantly lower in diabetics. There was a significant correlation between glycosylated haemoglobin and thyroid hormones. There was no correlation between serum insulin and thyroid hormones.     

Serum lipids in hypothyroidism: Our experience

In order to determine whether the screening of lipid profile is justified in patients with hypothyroidism we estimated serum lipids in cases having different levels of serum TSH. 60 patients of hypothyroidism in the age group of 20 to 60 yrs were studied for thyroid profile over a period of one year. On the basis of serum TSH level the cases were divided into three groups: In the first group TSH concentration was 8.8±2.99 μlU/ml, 95% confidence interval (Cl) 8.8±1.07, whereas serum total cholesterol and LDL-chol levels were 196±37.22 and 126±29.17 mg/dl respectively. The statistical analysis of these two groups showed a significant correlation between raised TSH levels and serum total cholesterol and LDL-chol (P<0.05 & P<0.01) respectively. We conclude that hypothyrodism is associated with changes in lipid profile.     

Thyroid disorders in women of Puducherry

Thyroid stimulating hormone (TSH), Free Thyroxine (FT₄) and Free Triiodothyronine (FT₃) were assayed in 505 women of this region. 60 women had previous history of thyroid disease. The remaining 445 women formed the “Disease free group”. A “Reference group” was obtained by excluding women with previous and present history of thyroid dysfunction. Of the total 505 women examined 15.8% had thyroid dysfunction and 84.2% were euthyroid. 11.5% were hypothyroid (9.5% sub-clinical) and 1.8% hyperthyroid (1.2% clinical). The geometric mean TSH for the total population was 2.65 μIU/ml. It was significantly (p=0.025) lower in the reference population 2.17 μIU/ml. There was no significant difference in the FT₃ and FT₄ values between groups. 19% of women over 60 years had elevated TSH above 4.5 μIU/ml. The 2.5 and 97.5 percentiles of the reference population was 1.1–5.2 μIU/ml. 6.1% of women in the reference group had TSH levels above the reference intervals. Hypothyroidism particularly sub-clinical hypothyroidism is predominantly present amongst women in this iodine sufficient region. Evaluation of thyroid status could help in early detection and treatment.     

Diagnostic strategies for subclinical hypothyroidism

The aim of this study is to delineate laboratory diagnostic strategies for subclinical hypothyroidism in patients who are clinically symptomatic but may have a normal thyroid profile. Tri — iodothyronine (T₃), thyroxine (T₄), thyroid stimulating hormone (TSH) and anti thyroid peroxidase antibodies (anti-TPO) were estimated on fasting blood samples from 99 patients using electrochemiluminescence methods on ELECSYS 1010 (Roche). 74% of study subjects had elevated anti-TPO levels.61% patients had subclinical hypothyroidism. 45 of the 61 subclinical hypothyroid patients had elevated anti-TPO levels (73%). This is an important finding suggesting an autoimmune etiology for subclinical thyroid dysfunction with a higher risk of developing overt hypothyroidism.