Normalized TSH strategy can improve the initial assessment of thyroid nodules

Area of Science:

• Endocrinology
• Nuclear Medicine
• Oncology

Background:

• Serum thyrotropin (TSH) is used for initial thyroid nodule assessment but has low sensitivity.
• Thyroid peroxidase antibody (TPOAb) interference is a key factor limiting TSH accuracy.
• Functional thyroid nodules (FTN) require accurate and early detection.

Purpose of the Study:

• To evaluate if normalized TSH (nTSH) improves diagnostic efficiency for thyroid nodules.
• To assess nTSH's ability to mitigate TPOAb interference in initial thyroid nodule evaluation.
• To compare nTSH strategy against traditional TSH testing.

Main Methods:

• Retrospective analysis of 90 FTN and 1038 non-FTN patients.
• Calculated regression coefficient (β) of TPOAb on TSH levels.
• Derived nTSH using the formula: nTSH = TSH - β * TPOAb.
• Compared diagnostic performance of nTSH versus TSH for FTN detection.

Main Results:

• nTSH showed improved sensitivity (50.00% vs 48.90%), specificity (87.70% vs 78.70%), and accuracy (84.67% vs 76.33%) compared to TSH.
• nTSH demonstrated higher positive predictive value (26.01% vs 16.60%) and negative predictive value (95.29% vs 94.67%).
• The differences in performance metrics between nTSH and TSH were statistically significant (p < 0.001).

Conclusions:

• Serum TPOAb testing is recommended for initial thyroid nodule assessment.
• Normalized TSH levels enhance diagnostic efficiency and specificity over traditional TSH assessment.
• Implementing nTSH can reduce unnecessary radioactive iodine scans (e.g., 99mTc-TS tests).