Development of a point-of-care assay system for high-sensitivity C-reactive protein in whole blood

C-reactive protein (CRP) is emerging as a potential risk predictor for future cardiovascular diseases (CVD). High sensitivity assays have been developed and applied for clinical purposes.

The fluorescence immunochromatographic assay was employed to detect and quantify CRP in whole blood. It consisted of a fluorescence (FL) antibody detector buffer, a test strip housed in a disposable cartridge, and a laser fluorescence scanner. Whole blood sample was mixed with detector, loaded onto a cartridge, incubated for 10 min, and the concentration of CRP was measured in a laser fluorescence scanner. The linearity, limit of detection (LOD), and performance of new assay system was tested and evaluated. The comparability of assay was examined with an automated reference method.

With the new assay system, a reliable correlation of coefficient (r) was obtained between the ratio value (A(T)/A(C)) and a concentration of CRP in samples. The linearity fell in the range of 0-10 mg/l of CRP, and the analytical detection limit was 0.133 mg/l of CRP. The mean recovery of the control was 105.2% in a working range. The precision of the intra- and inter-assay in a range of 0.5-6 mg/l was CVs <6% and <8%, respectively. The new fluorescence immunochromatographic assay system correlated well with a traditional immunoturbidimetric assay for quantification of CRP concentration (r=0.955, N=90).

The fluorescence immunochromatographic assay is fast, reliable, and a reproducible platform for point-of-care testing (POCT) of high-sensitive (hs)-CRP in whole blood.