Evaluation of 3 Point-of-Care Testing Hematology Analyzers for White Blood Count

Abstract In the past few years, several small hematology analyzers were introduced for point-of-care testing (POCT) purposes. The POCT hematology analyzers can be used for the same purposes as centralized systems, but the possibility to use capillary blood from a fingerprick is a major advantage in several situations. The 3 tested POCT systems were the WBC DIFF system of Hemocue (Sweden), the Microsemi C-reactive protein of Horiba (Japan), and the Norma Icon hematology analyzer (Austria). The Microsemi and WBC DIFF were evaluated simultaneously. For the agreement with the laboratory method, 125 patient samples (EDTA blood, patients from general practitioners) were compared with the Sysmex XE-2100. For the agreement of the Norma Icon with the laboratory method, 188 patient samples (EDTA blood, 90 clinical and 98 polyclinic patients) were compared with the Sysmex XN-9000. The intra-assay coefficients of variation of the various samples (low, medium, high) are in all systems better than stated by the manufacturer [white blood cell (WBC), 3%; or fractions, 5%] except for monocytes, which were approximately 25%. Ordinary linear regression analysis and Bland-Altman difference analysis showed good results for the WBC and granulocyte or neutrophil comparisons. Lymphocyte comparisons showed less favorable results in the Bland-Altman analyses. In the case of the monocytes, the correlation coefficients were inadequate for linear regression. All 3 POCT hematology analyzers seemed to be suitable for WBC measurements and differential analyses of lymphocytes and granulocytes or neutrophils in venous blood, but evaluations with capillary fingerprick blood will be necessary.