Performance profile of an updated safety measure rapid assay for bacteria in platelets

BACKGROUND: The Verax PGD rapid test for bacteria in platelets (PLTs) has been updated to simplify workflow and improve specificity and sensitivity by employing a novel sequential format. The performance of this updated version, called PGDprime, was evaluated to determine its suitability for use as an FDA‐cleared “safety measure” to supplant the current PGD test. STUDY DESIGN AND METHODS: Three consecutive cGMP‐manufactured lots of PGDprime were evaluated for specificity (at three separate sites), sensitivity, reproducibility, interfering substances, assay robustness, and detection in analytical growth and ultralow‐inoculum growth studies. PGDprime's performance was compared to that of PGD. RESULTS: Specificity studies yielded no false‐positive results among 3802 individual indate PLTs of seven different types (observed specificity, 100%). PGDprime detected all 10 PGD claim bacteria at the same limit of detection or better. Wild‐type Gram‐negative bacteria growing in PLTs were detected at earlier elapsed times than PGD by 12 to 30 hours. In growth studies, PGDprime detected bacteria growing in PLTs within the same 12‐hour interval as PGD or 12 to 48 hours earlier. Assay reproducibility was not affected by operator, day of test, or manufacturing lot. PGDprime tolerated a wide variation in volume transfers, timing, temperature, and relative humidity and was not affected by 15 of 16 potential interferents found in samples at extremely high or low levels. CONCLUSION: The PGD test has been successfully updated to PGDprime with an innovative sequential assay format to deliver a robust simplified workflow and improved specificity and sensitivity.