Abstract
Thyroid diseases are common worldwide. In India too, there is a significant burden of thyroid diseases. According to a projection from various studies on thyroid disease, it has been estimated that about 42 million people in India suffer from thyroid diseases. In the present paper, we address the current use of TSH as the dominant parameter in thyroid function testing, to ascertain its normal reference range, explain some major limitations of this approach, and attempt to suggest areas of possible improvement. The study was conducted in the super speciality hospital, Department of Biochemistry, GMC, Jammu. Total number of subjects was 50 (25 males, 25 females) aged 30-70 years. 2ml of venous blood was collected from antecubital vein under aseptic conditions from each individual. Whole blood specimen were analysed for TSH by chemiluminescence. The normal range of TSH was found to be 0.35 mu/L - 4.95 mu/L, for males and females alike. The corresponding values reported by standard laboratories like Dr. Lal Path Labs: 0.35 mu/L - 5.50 mu/L and SRL Labs: 0.35 mu/L to 5.25 mu/L, were comparable (p>0.05). The TSH value has to change by at least 30% to discriminate between a natural variation and a real progression. Additional influences such as gender, age, or time of sampling are less pronounced. A better understanding of thyroid hormone homeostasis including the role of TSH in the context may therefore aid in improving the diagnostic reliability of TSH measurement from both a methodological and clinical perspective.