Clinical evaluation of a new, point-of-care hemocytometer

Objective: This study was designed to compare results obtained with a new point-of-care hemocytometer with those of two established (paint-of-care and laboratory-based) instruments. Design: To compare CBC values between established laboratory-based and point-of-care instruments, measurements were performed on routinely obtained blood specimens for CBC analysis in our institutional laboratory (phase I) and on specimens from cardiac surgical patients before initiation of cardiopulmonary bypass and after discontinuation of cardiopulmonary bypass in phase II. Setting: Surgical and hospitalized patients at a tertiary care center. Patients: Measurements were obtained by using blood specimens obtained from 141 hospitalized patients from different services (phase I) or from a consecutive series of 204 patients undergoing cardiac operations (phase II). Measurements and Main Results: Hemoglobin (HGB), platelet count (PLT), red blood cell count, and white blood cell count (WBC) were measured with two on-site and one laboratory-based instruments. Hematocrit (HCT) was calculated by using measured variables. Linear regression demonstrated good correlations between Ichor and T540 HGB (r² = .95), HCT (r² = .95), PLT (r² = .94), and WBC (r² = .95) results (n = 408); similarly, good correlations were observed with Coulter STKS HGB (r² = .92), HCT (r² = .91), and PLT (r² = .94) results (n = 141). The relationship between Ichor and Coulter STKS WBC (r² = .27) was poor; however, when two Ichor-derived outlier values (>50) were excluded, the relationship was very good (r² = .99). Bias analysis (mean ± SD) demonstrated similar results between Ichor and T540 HGB (0.003 ± 0.5), HCT (-0.21 ± 1.5), WBC (0.79 ± 1.3), and PLT values (-9.2 ± 16.8) as well as STKS HGB (-0.96 ± 0.7), HCT (-0.69 ± 2.3), WBC (-0.62 ± 5.8), and PLT values (-10.2 ± 21.4). Conclusions: The Ichor hemocytometer provides accurate hematologic results that can facilitate rapid quantitative assessment of CBC variables and thus may be clinically useful, especially in critically ill patients.