A solid phase chemiluminescent immunoassay (LIA) for testosterone glicuronide in diluted urines

Area of Science:

• Endocrinology
• Clinical Chemistry
• Assay Development

Background:

• Testosterone 17 beta-D-glicuronide (TG) is an important urinary metabolite for assessing androgen status.
• Existing methods for TG measurement may be time-consuming or involve radioisotopes.

Purpose of the Study:

• To develop and validate a novel, rapid, and non-radioactive chemiluminescent immunoassay (LIA) for quantifying urinary TG.
• To compare the performance of the LIA method with a established radioimmunoassay (RIA).
• To investigate urinary TG excretion patterns in hirsute women.

Main Methods:

• A solid-phase chemiluminescent immunoassay using a TG-isoluminol conjugate (TG-ABEI) as the tracer.
• Passive adsorption of an IgG fraction of TG-BSA antiserum to polystyrene tubes.
• Measurement of chemiluminescence at high pH after binding and washing steps.
• Validation of specificity, accuracy, sensitivity, and precision.
• Comparison of LIA results with RIA measurements.

Main Results:

• The LIA method demonstrated good agreement with the RIA method (r = 0.95).
• The assay is validated for specificity, accuracy, sensitivity, and precision.
• The LIA method is rapid and avoids radioisotopes and centrifugation.
• Preliminary data indicate higher 24-hour urinary TG excretion in hirsute women compared to controls.

Conclusions:

• The developed chemiluminescent immunoassay provides a reliable and efficient method for measuring urinary testosterone 17 beta-D-glicuronide.
• This assay offers significant advantages over traditional methods, including speed and safety.
• The findings suggest a potential role for urinary TG as a biomarker in the evaluation of hirsutism.