Performance Characteristics of a Cystatin C Immunoassay with Avian Antibodies

Abstract

Background: A new particle-enhanced turbidimetric immunoassay (PETIA) with avian antibodies for measuring serum/plasma cystatin C has been developed. The performance characteristics of the assay are described. Methods: Measurements were performed on a Roche Modular P and on an Abbott Architect ci8200 using Gentian cystatin C immunoassay.

Results: Measuring range was 0.3–8.0 mg/L. Reference range was 0.57–1.09 mg/L. Total analysis time was 10 minutes. Linearity was absolute over the whole assay range. Recovery of samples and controls was within 98.6–109.4%. Total imparticle enhanced nephelometric cystatin C immunoassay (PENIA) by linear regression resulted in a slope within 0.97–1.02 and intercept within ±0.05 mg/L. Interference studies with drugs, anticoagulants, intralipid ( 11g/L), triglycerides ( 14 g/L) and bilirubin (420mg/L) antibodies, no interference with rheumatoid factor was observed. No carry-over was 6%) were both below 0.33 mg/L, which is less than the lowest standard. Sample stability was up to one month at 2–8°C. Stability of the reagents at 2–8°C was estimated to be 24 months.

Stability of the reagents in use was minimum 9 weeks.

Conclusions: Gentian cystatin C PETIA is shown to have excellent performance between methods. Interference results are improved due to avian antibodies and a broader span of the calibration curve. Avian antibodies are also known to have better immune response than mammalian antibodies towards mammalian antigens.