Validation of the UST thyroid scoring index against ultrasensitive assays for thyroid-stimulating hormone and free thyroxine
Philippine Journal of Internal Medicine
Background: Clinical manifestations of thyroid dysfunction are variable. The UST Scoring Index for thyroid disorders, formulated in the 1990s to evaluate thyroid functional status, was based on total thyroid hormone levels and thyroidal iodine uptake. However, with the advent of newer and more sensitive tests, the recommendations and practice now dictate the use of thyrotropin (TSH) and free thyroxine (FT4) levels in the confirmation of thyroid dysfunction. Objective: To validate the UST Scoring Index for thyroid disorders using TSH and FT4. Methods/Results: The UST Clinical Scoring Index was administered to 170 patients presenting for thyroid-related complaints. Thyroid function tests were then requested (TSH and Free T4) and they were classified according to biochemical status. We obtained the following: 43 hyperthyroid, 102 euthyroid and 25 hypothyroid subjects. The mean TSH for the 3 groups were 0.08, 1.28, and 41.50 uIU/mL respectively (NV 0.27-3.75.) Mean FT4 levels were 36.18, 18.33, and 8.43 pM/L respectively (NV 10.3-25.0.) The most frequent findings in the biochemically hyperthyroid group were thyroid enlargement (88%), easy tiredness (74%), palpitations (70%), and nervousness (65%); in the euthyroid group, easy tiredness (62%), thyroid enlargement (54%), palpitations (53%), and irritability (49%); in the hypothyroid group, easy tiredness (64%), exertional dyspnea (52%), weight gain (44%), and constipation (44%.) The UST scoring index for thyroid disorders has a sensitivity of 67%, specificity of 84%, and accuracy rate of 80%, with AUC of 0.850 on ROC analysis for the detection of hyperthyroidism. For detecting hypothyroidism, it has a sensitivity of 40%, specificity of 92%, and asccuracy rate of 85%, with AUC 0.7553 on ROC analysis. Conclusion: The UST scoring index for thyroid disorders has good sensitivity, specificity and accuracy rate based on ROC when validated using TSH and FT4 for the detection of hyperthyroidism and hypothyroidism.
Galia, A., Andag-Silva, A., Kho, S., San Luis, T., & Magboo-Gaviola, M. (2010). Validation of the UST thyroid Scoring index against ultrasensitive assays for thyroid-stimulating hormone and free thyroxine. Philippine Journal of Internal Medicine, 48(1), 15-23.