| Abstract: |
An evaluation of a Coulter Counter Model S-Plus IV® hematology analyzer was undertaken at Memorial Sloan-Kettering Cancer Center to assess performance characteristics and to determine accuracy in analyzing both normal and clinical specimens. Special emphasis was placed on the platelet parameter. Precision, linearity, and carryover were found to be well within the manufacturer's specification. A total of 222 patient samples were analyzed in the routine laboratory and on the Model S-Plus IV. Coefficients of correlation of 0.99 or higher were obtained for white blood cell count (WBC), red blood cell count (RBC), hemoglobin (Hgb), platelets (Plt), except mean cell volume (MCV) (r = 0.93). Results from 99 selected normal samples were compared with those from manual reference methods. Coefficients of correlation of 0.98 or higher were obtained for WBC, RBC, and Hgb. For MCV, the correlation coefficient was 0.85 and for Plt, 0.89 was obtained. The lower coefficient of correlation for these two parameters may be a function of the imprecision of the manual reference methods. In a previous study with an original Model S-Plus, the Plt parameter occasionally exhibited spuriously high counts. With the advent of third-generation S-Plus instruments, represented by the Model S-Plus IV, the possibility of reporting aberrant Plt values virtually has been eliminated. Data from the current study verify this. However, 93% of the flagged Plt results proved to be accurate, checking slides on these introduced inefficiencies in the laboratory. |
