Feasibility of routine individual donation testing for West Nile virus RNA during epidemic season using the investigational Roche cobas TaqScreen West Nile virus test and cobas s 201 system prototype

Abstract

Minipool (MP) screening for West Nile virus (WNV) RNA may fail to detect presumptive viremic donations (PVDs) detectable by individual donation screening (IDS). Most blood centers switch collection regions to IDS when PVD detection by MP screening reaches a certain frequency. Use of IDS for all donations during WNV season was assessed during a clinical trial of the Roche cobas TaqScreen WNV test. Also evaluated was whether PVD detection reliably identifies regions that should be targeted for IDS. Test results, deviation reports, and service records were reviewed for 13.5 weeks of IDS in 2006 and 11.5 weeks of IDS in 2007. Numbers of PVDs and clinical WNV cases were obtained from public health and AABB Web sites and regional donor centers. Approximately 1000 donations were tested per week divided in six test runs. Each run required 1.2 shifts of technologists plus volunteers. A total of 7.2 percent of samples were initially unreportable in 2006 and 4.8 percent in 2007. Of 26,952 donations screened by IDS, none were reactive for WNV. A comparison of PVD and clinical case reports indicates that PVD detection in areas with intermediate or high clinical case prevalence may not reach commonly used criteria for triggering testing to IDS. Seasonal IDS was feasible using the cobas TaqScreen WNV test on the s 201, although staffing was impacted and a relatively high number of samples required retesting because of error messages. Seasonal IDS utilizing this highly specific assay may be a reasonable alternative to IDS triggered by regional PVD detection.