Evaluation of complete blood count results from a new, on-site hemocytometer compared with a laboratory-based hemocytometer

Objective: To compare point-of-care results obtained from an on-site hemocytometer with values provided by an institutional laboratory instrument. Design: A prospective laboratory evaluation. Setting: The central laboratory and cardiac surgical intensive care unit of a university-affiliated tertiary care center. Patients: Normal range comparison was performed using blood specimens routinely obtained from 48 hospitalized patients for complete blood count analysis. The second evaluation was performed on blood specimens routinely obtained (in the intensive care unit) after cardiac surgery involving extracorporeal circulation in a series of 187 consecutive patients. Measurements and Main Results: Hemoglobin concentration, platelet count, mean corpuscular volume, mean platelet volume, and red and white blood cell counts were measured with both on-site (MD 16, Coulter Electronics, Hialeah, FL) and laboratory (STKS, Coulter Electronics) instruments. Hematocrit and red cell distribution width were calculated using measured variables. Blood specimens were obtained from two distinct patients series. To evaluate measurement values within the normal range, a series of 48 routinely obtained blood specimens for complete blood count analysis in our institutional laboratory were utilized for concurrent analysis with the on-site hemocytometer. To evaluate measurement values out of the normal range, a second comparison involved measurements performed on blood specimens obtained in the cardiac surgical intensive care unit for complete blood count analysis. Linear regression demonstrated good correlations between on-site and laboratory hemoglobin concentration (r² = .97), hematocrit (r² = .95), platelet count (r² = .97), mean corpuscular volume (r² = .91), red cell distribution width (r² = .80), and red (r² = .95) and white (r² = .96) blood cell count results. A marginal correlation was observed between mean platelet volume values (r² = .47). Bias analysis (mean ± 2 SD) demonstrated similar measurements between on-site and laboratory hemoglobin concentration, hematocrit, platelet count, red blood cell count, white blood cell count, mean platelet volume, mean corpuscular volume, and red cell distribution width. Conclusions: On-site hemoglobin concentration, hematocrit, white blood cell count, red blood cell count, red cell distribution width, and platelet count values compare well with those results obtained from the laboratory. The MD 16 hemocytometer (Coulter Electronics) provides on-site hematologic results that can provide an accurate and rapid quantitative assessment of platelets, and red and white blood cells. Rapid access to information obtained from this type of system may be clinically useful, especially in critically ill patients.