Fast detection of ß2 microglobulin in patient blood by a handhold centrifugal microfluidic device

Abstract

Elevating blood ß2 microglobulins (ß2 M) level is one of the indicators of diseases such as diabetes, kidney failure, and tumors. A centrifugal microfluidic chip was designed to conduct latex immunoagglutination assays for testing ß2 M. A handhold centrifuge was assembled to drive solution mixing in the microfluidic chip. An office scanner recorded the binding of ß2 M to the latex beads induced agglutination, reducing reliance on expensive scientific equipment and avoiding environmental light interference. The results revealed that the degree of beads agglutination was proportional to the grayscale value changes (∆G). The ß2 M testing can be accomplished using a 1.25 µL blood sample, and the testing time is 10 min. The limit of detection is 0.0335 mg/L. The recovery rate calculated by the measured and spiked ß2 M concentration ratio is 91.8–111.8%. The centrifugal chip was applied to test 50 patients’ samples. The confusion matrix analyzed the rate of false positives, false negatives, true positives, and true negatives for the ß2 M chip-based test, showing the sensitivity of the ß2 M chip is 77.3%, the specificity is 82.1%, and the efficiency is 80%. The Area Under the Curve analysis shows that the cutoff value (∆G = 1.011) of ∆G in predicting ß2 M elevating has a sensitivity of 100% (95% CI: 92.87% −100%) with the specificity of 92% (95% CI:81.6–96.85%).