Sensitive albuminuria analysis using dye-binding based test strips.

BACKGROUND

Populations at increased risk for chronic kidney disease should be screened for albuminuria. Possibilities of advanced urine strip readers based on complementary metal oxide semiconductor (CMOS) sensor technology were investigated for obtaining quantitative albuminuria results.

METHODS

Reflectance data of test strips (Sysmex UFC 3500 reader+CMOS) were compared with albuminuria (BNII) and with proteinuria (Cobas 8000). Urinary creatinine was assayed using a Jaffe-based creatinine assay (Cobas 8000).

RESULTS

Calibration curve was made between 11.5 and 121.5mg/L with detection limit of 5.5mg/L. Within-run CV values of reflectance data were 0.21% (UC-Control L; 10mg/L) and 0.37% (UC-Control H; >150mg/L) for albumin, and 0.71%/3.97% for creatinine. Between-run CV values were 0.24%/0.42% for albumin and 0.93%/5.13% for creatinine. A strong correlation (r=0.92) was obtained between albuminuria (BNII) and protein strip reflectance data. Creatinine reflectance data correlated well with Jaffe-based urinary creatinine data (r=0.90). Albumin:creatinine ratio obtained by test strip and by wet chemistry showed a good correlation (r=0.59). Carbamylated, glycated and partially hydrolyzed isoforms of albumin could be detected by test strip.

CONCLUSIONS

Dye-binding based albumin test strip assay in combination with a CMOS based reader would potentially allow quantitative analysis of albuminuria and determination of albumin:creatinine ratio.