Claros System: A Rapid Microfluidics-Based Point-of-Care System for Quantitative Prostate Specific Antigen Analysis from Finger-Stick Blood.

INTRODUCTION

Determination of circulating prostate specific antigen (PSA) is commonly used in the diagnosis and treatment monitoring of prostate cancer [1]. Presently, PSA testing is performed in centralized laboratories, which is associated with prolonged time between venipuncture and the PSA value being available. In this prospective study, we present a new and rapid test system for the quantitative determination of PSA levels from finger-stick blood.

METHODS

The Claros1 analyzer is a rapid microfluidics-based point-of-care system for quantitative PSA analysis from 10-µl finger-stick blood that requires only 10 min for testing. Total PSA concentrations by the Claros system in 100 consecutive asymptomatic men (median age 57 years, range 44-81 years) were compared with two commercially available, commonly used PSA assays (Abbott and Elecsys by Roche) performed by a reference laboratory.

RESULTS

Eighty-six percent of finger-stick blood-borne probes from 100 men were evaluable for PSA testing by the Claros1 analyzer system. In 13/14 cases the expiry date of the microfluid cassettes of the Claros system was exceeded and one blood puncture was performed inadequately. The correlations between the Claros results and OPKO-Abbott and OPKO-Roche assay results were high, with R values of 0.982 and 0.985, respectively. The R value for the Roche-Abbott correlation was 0.991 with a slope value of 1.160. Prostate cancer was diagnosed in seven cases, with a median PSA of 1.8 ng/ml in the Claros group compared to 1.75 ng/ml and 2.1 ng/ml in the Abbott and Roche groups, respectively.

CONCLUSION

The Claros1 PSA assay combines the advantages of rapid, accurate detection with a low required sample volume, allowing the analysis to be performed using finger-stick blood. Provided that further analysis proves the reproducibility of the test, it may help to reduce the number of office visits, thus decreasing costs to the health care system.