A quantitative C-reactive protein assay using latex agglutination in microtiter plates

Area of Science:

• Clinical Chemistry
• Immunodiagnostics
• Biochemical Assays

Background:

• C-reactive protein (CRP) is a key biomarker for inflammation and infection.
• Accurate and rapid quantification of CRP is crucial for timely clinical decision-making.
• Existing CRP assays may require complex procedures or longer turnaround times.

Purpose of the Study:

• To develop and validate a simple, rapid, and quantitative latex agglutination assay for C-reactive protein (CRP).
• To establish the assay's performance characteristics, including sensitivity, linearity, reproducibility, and correlation with established methods.

Main Methods:

• Quantitative latex agglutination assay utilizing anti-CRP coated particles.
• Measurement of agglutination via absorbance decrease at 405 nm after vortex agitation.
• Serum samples were analyzed with minimal dilution steps, with standard curves established from 5 to 150 mg/l.

Main Results:

• The assay demonstrated a linear range from 5 to 150 mg/l, with up to 300 mg/l determinable without further dilution.
• Assay completion in 30 minutes with only two pipetting steps post-dilution.
• Excellent reproducibility: within-assay (4.4–7.5%) and between-assay (9.3–12.2%).
• High correlation with automated nephelometry (r=0.96) and turbidimetry (r=0.97).

Conclusions:

• The developed latex agglutination assay is a simple, rapid, and reliable method for quantitative CRP determination.
• The assay offers excellent reproducibility and strong correlation with existing methods, suitable for clinical use.
• This assay provides a valuable tool for diagnosing and monitoring inflammatory conditions.