Sensitivity and specificity of clinical diagnosis of Graves’ disease and non-Graves’ disorders compared to serum TSH receptor antibodies

Abstract

Background and objective: Sensitivity and specificity of clinical diagnosis of different hyperthyroid conditions were studied and compared with serum thyrotropin receptor antibodies test, as a standard test for diagnosing Graves' disease. This study aimed to assess the degree of sensitivity and specificity of clinical diagnosis of hyperthyroid conditions compared to the thyrotropin receptor antibodies test, which was selected as a standard test for diagnosis of Graves’ disease in the study. Methods: We studied patients presenting to endocrine outpatient clinics and other outpatient settings in Erbil city, presenting with clinical features of thyrotoxicosis. Serum or plasma thyroid-stimulating hormone, free T4, and thyrotropin receptor antibodies measurements were done for all the patients. Thyroid peroxidase antibodies and thyroid ultrasonography were done for most patients. Radioactive thyroid uptake was available for a limited number of patients. Sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and accuracy index of clinical diagnosis of the thyrotoxicosis cases were calculated. Results: A total of 150 patients were included in our study, female 102, males 48, mean age 38 (range 16-78) years, pretest diagnosis of (Graves’ disease N=58, and non-Graves’ disease N=92 and posttest diagnosis of (Graves’ disease n= 59 vs. non-Graves’ disease=91). Sensitivity of 74.6%, specificity (84.60%), positive predictive value (75.9%), negative predictive value (83.7%), positive likelihood ratio (4.847), negative likelihood ratio (0.30), and accuracy index (80.7%) of the clinical diagnosis were estimated. Conclusion: The study showed that clinical diagnosis of Graves' disease and non-Graves’ disease disorders, using thorough clinical examination and primary essential investigations, has high sensitivity and specificity index. However, the serum thyrotropin receptor antibodies test remains the standard method in the differential diagnosis of Graves' disease. Other studies are needed to study ultrasound and scintigraphy compared to the thyrotropin receptor antibodies test.

Keywords

• graves’ disease
• tsh receptor antibodies
• thyrotoxicosis
• toxic multinodular goiter
• thyroiditis