Analytical Variation Between Two Different TSH Reagents from the Same Manufacturer.

Area of Science:

• Clinical Chemistry
• Immunoassay Technology
• Endocrinology

Background:

• Thyroid stimulating hormone (TSH) immunoassays are crucial for diagnosing thyroid dysfunction.
• Variability in TSH assay results across different platforms and kit generations can affect clinical decisions.
• Consistent and accurate TSH measurement is essential for proper patient management.

Purpose of the Study:

• To compare the performance of two TSH immunoassays from the same manufacturer, Siemens Healthineers.
• To identify and quantify any discrepancies or bias between the TSH assay methods.
• To assess the potential clinical impact of observed assay differences on thyroid dysfunction diagnosis.

Main Methods:

• A method comparison study was conducted using two TSH immunoassay kits from Siemens Healthineers.
• Patient samples were analyzed using both TSH assay methods.
• Statistical analysis was performed to determine the bias and proportional error between the two assays.

Main Results:

• A significant proportional error was detected between the two TSH assays.
• A bias of -3.71 mIU/L was observed, indicating higher TSH values with one assay compared to the TSH3-Ultra kit.
• The identified bias suggests that TSH assay results may lead to overestimation of TSH levels.

Conclusions:

• The observed proportional error and bias between TSH assays can lead to misinterpretation of results.
• This discrepancy may result in incorrect categorization of patients with hypothyroidism and subclinical hypothyroidism.
• In-house validation and method comparison studies are crucial to ensure assay performance and prevent clinical errors in thyroid dysfunction evaluation.