Radioimmunoassay of total urinary estrogens

Area of Science:

• Endocrinology
• Clinical Chemistry
• Analytical Chemistry

Background:

• Accurate measurement of total estrogens in urine is crucial for monitoring endocrine function and diagnosing related conditions.
• Existing methods for estrogen determination can be time-consuming or lack the required sensitivity and specificity.

Purpose of the Study:

• To develop and validate a rapid radioimmunoassay (RIA) for quantifying total estrogens in urine.
• To assess the assay's performance characteristics, including precision, accuracy, and correlation with established methods.

Main Methods:

• Urine samples were processed using XAD-2 resin for estrogen extraction.
• Extracted estrogens were acid-hydrolyzed and subsequently quantified using a validated radioimmunoassay.
• Assay performance was evaluated through within-run and between-run coefficient of variation (CV) analyses.
• Correlation with a standard fluorometric assay was determined using linear regression analysis.

Main Results:

• The radioimmunoassay demonstrated high precision with within-run coefficients of variation (CV) below 5% for estriol values between 6.0 and 100 µg/L.
• Between-run CV was 19.6% at an estriol concentration of 16.8 µg/L.
• A strong correlation (r=0.96) was observed between the RIA results (y) and a standard fluorometric assay (x), with the regression equation y = 2.18x - 6.70 µg/L.
• The assay allows for the determination of urinary estrogens in both pregnant and non-pregnant individuals within a 4-hour timeframe.

Conclusions:

• The developed radioimmunoassay provides a rapid, precise, and accurate method for determining total estrogens in urine.
• This RIA method is suitable for clinical applications, enabling timely assessment of estrogen levels in diverse patient populations.
• The assay's efficiency and reliability support its use in routine diagnostic laboratories.