Sensitive, rapid procedure for time-resolved immunofluorometry of lutropin

Area of Science:

• Biochemistry
• Immunology
• Analytical Chemistry

Background:

• Accurate quantification of lutropin (LH) is crucial for diagnosing reproductive disorders and monitoring fertility treatments.
• Existing methods like radioimmunoassay (RIA) involve radioactive isotopes, posing handling and disposal challenges.
• Development of sensitive, non-isotopic assays is essential for routine clinical diagnostics.

Purpose of the Study:

• To develop and validate a new time-resolved immunofluorometric assay (TR-IFMA) for serum lutropin (LH) quantification.
• To offer both a rapid assay for monitoring and a sensitive assay for hyposecretory states.
• To compare the performance of the new assay with existing methods.

Main Methods:

• Utilized a "sandwich" immunoassay principle with time-resolved fluorescence detection.
• Employed a monoclonal antibody against the LH alpha-subunit immobilized on microtiter wells for capture.
• Used a biotin-labeled monoclonal antibody and a streptavidin-europium chelate (BCPDA) complex for signal amplification and detection.

Main Results:

• The assay demonstrated reliable quantification of lutropin (LH) in serum up to 240 int. units/L.
• A rapid protocol (under 60 min) was suitable for monitoring ovulatory LH surges.
• A regular protocol (150 min) offered high sensitivity (0.5 int. units/L) for detecting hyposecretory LH levels.
• Results showed good correlation with RIA, IRMA, and another TR-IFMA.

Conclusions:

• The developed time-resolved immunofluorometric assay provides a sensitive and versatile method for serum lutropin (LH) measurement.
• The assay offers flexibility with rapid and regular protocols catering to different clinical needs.
• This non-isotopic method is a viable alternative to traditional radioimmunoassays for LH quantification.