Alan H B Wu1, Jill Sellers2. 1. Department of Laboratory Medicine, University of California, San Francisco, CA; alan.wu@ucsf.edu. 2. Medavera, Inc., Springfield, MO.
Abstract
BACKGROUND: The XW-100 hematology analyzer (Sysmex America) is the first complete blood count (CBC) instrument waived by the US Food and Drug Administration. This analyzer also tests for a 3-part white blood cell count differential. METHODS: The XW-100 analyzer was evaluated for preanalytical specimen variables including the need for mixing, specimen storage conditions, freeze-thaw cycles, the effect of under filling of tubes, precision, linearity, carryover, limits of the blank, detection, and quantification and interferences from common and CBC-specific substances. The clinical study examined 586 blood samples from 6 CLIA-waived clinical sites and 6 paired moderately complex sites. The point-of-care sites had different medical specialties and were using inexperienced operators. The results of 8 measurements and 4 calculated parameters were compared to a moderately complex point-of-care hematology analyzer (pocH-100i, Sysmex). RESULTS: The precision was <6% for all analytics, and there was no carryover noted. Samples containing interfering substances were appropriately flagged or suppressed by the instrument. The correlation to the predicate analyzer was highly concordant, producing near unity slope and intercept and minimal bias. Delays from sample collection to testing resulted in decreased performance. The percentage of samples inside the allowable error was >98.8% for all parameters studied. CONCLUSION: This CLIA-waived hematology analyzer produces acceptable results and can be used in offices and clinics.
BACKGROUND: The XW-100 hematology analyzer (Sysmex America) is the first complete blood count (CBC) instrument waived by the US Food and Drug Administration. This analyzer also tests for a 3-part white blood cell count differential. METHODS: The XW-100 analyzer was evaluated for preanalytical specimen variables including the need for mixing, specimen storage conditions, freeze-thaw cycles, the effect of under filling of tubes, precision, linearity, carryover, limits of the blank, detection, and quantification and interferences from common and CBC-specific substances. The clinical study examined 586 blood samples from 6 CLIA-waived clinical sites and 6 paired moderately complex sites. The point-of-care sites had different medical specialties and were using inexperienced operators. The results of 8 measurements and 4 calculated parameters were compared to a moderately complex point-of-care hematology analyzer (pocH-100i, Sysmex). RESULTS: The precision was <6% for all analytics, and there was no carryover noted. Samples containing interfering substances were appropriately flagged or suppressed by the instrument. The correlation to the predicate analyzer was highly concordant, producing near unity slope and intercept and minimal bias. Delays from sample collection to testing resulted in decreased performance. The percentage of samples inside the allowable error was >98.8% for all parameters studied. CONCLUSION: This CLIA-waived hematology analyzer produces acceptable results and can be used in offices and clinics.