Plasma 17-hydroxyprogesterone determination with two commercial immunoassays

Area of Science:

• Endocrinology
• Clinical Chemistry
• Assay Development

Background:

• Accurate measurement of plasma 17-hydroxyprogesterone (17-OH-P) is crucial for diagnosing endocrine disorders.
• Commercially available immunoassay kits are widely used but require validation for specific populations.

Purpose of the Study:

• To evaluate the accuracy of two commercial immunoassay kits for plasma 17-OH-P determination.
• To compare radioimmunoassay (RIA) and enzyme-immunoassay (EIA) kits against a validated in-house RIA method.
• To identify potential interferences in specific patient groups.

Main Methods:

• Plasma 17-OH-P was measured using a CIS RIA kit and a Serono EIA kit.
• RIA was performed directly on plasma and on plasma extracts; EIA used plasma extracts only.
• Results were compared to an in-house RIA with extraction and Sephadex LH 20 chromatography.
• Assays were conducted on 27 infants (<1 year) and 33 women in the follicular phase.

Main Results:

• Both commercial kits consistently overestimated 17-OH-P levels.
• 17-hydroxy-pregnenolone (17-OH-5P) sulfate interfered with the CIS RIA when used directly on infant plasma.
• 17-OH-5P interfered with the Serono EIA in infants and the CIS RIA in women when using plasma extracts.

Conclusions:

• The evaluated commercial RIA and EIA kits are not adequate for accurate 17-OH-P determination in infants and women during the follicular phase.
• Interference from 17-OH-5P is a significant issue affecting the reliability of these kits.
• Further validation and potentially modified assay procedures are needed for reliable 17-OH-P measurements in these demographic groups.