Solid phase radioimmunoassays for human C-reactive protein

Area of Science:

• Immunology
• Biochemistry
• Clinical Chemistry

Background:

• Human C-reactive protein (CRP) is a key inflammatory marker.
• Accurate and rapid quantification of CRP is crucial for diagnosing and monitoring various conditions.
• Existing methods may lack the desired sensitivity or speed for certain clinical applications.

Purpose of the Study:

• To develop and validate two novel, rapid, and sensitive radioimmunoassay methods for human CRP.
• To assess the performance characteristics, including sensitivity and precision, of the new assays.
• To determine reference ranges for CRP in a normal adult population and detect its presence in other bodily fluids.

Main Methods:

• Establishment of two radioimmunoassay (RIA) methods for human CRP.
• Utilized antiserum coupled to magnetizable cellulose particles for efficient phase separation.
• Single antibody method (solid phase anti-CRP) and double antibody method (fluid phase anti-CRP with solid phase anti-rabbit IgG).

Main Results:

• Single antibody RIA: 50 µg/l sensitivity, 1-hour incubation, 10% CV (intra- and inter-assay).
• Double antibody RIA: 3 µg/l sensitivity, overnight incubation, 10% CV (intra- and inter-assay).
• Median CRP in normal adult sera: 800 µg/l (range 70–29,000 µg/l); 90% < 3 mg/l, 99% < 10 mg/l. Low CRP levels detected in amniotic and cerebrospinal fluids.

Conclusions:

• The developed radioimmunoassays are rapid, sensitive, and precise for human CRP measurement.
• These assays are suitable for quantifying CRP in serum and detecting low levels in other biological fluids.
• The findings provide valuable reference ranges and demonstrate the utility of these new methods in clinical settings.