EVALUATION OF AUTOMATED BASOPHIL COUNTING BY USING FLUORESCENCE-LABELED MONOCLONAL-ANTIBODIES

The shortcomings of current methods of basophil enumeration detract fr om the clinical value of the basophil count. Moreover, sophisticated a nd costly techniques of automated basophil counting hardly can be vali dated for lack of a suitable reference method. We investigated whether a flow cytometric technique using double staining with fluorescence-l abelled monoclonal antibodies (mAb) CD45-FITC and CD14-PE on a Coulter Epics Profile II could be used to evaluate basophil counting performa nce of hematology analyzers. The technique was compared with the 800-c ell manual differential, the Coulter STKS, and the Cobas Argos 5 Diff. Precision: STKS,Argos and Profile II showed a precision analogous to a 2,173, 2,250-, and 14,705-cell differential, respectively, illustrat ing the superiority of automated methods. Accuracy (150 normal and abn ormal samples): Using the Profile II as reference the STKS showed a no tably weaker correlation than the Argos (r = 0.581 and 0.718, respecti vely), although this difference was nearly concealed when the imprecis e manual differential served as reference (r = 0.517 and 0.562, respec tively). The Profile II correlated relatively well with the manual dif ferential (r = 0.730). Analyzing 137 healthy adult subjects, we obtain ed a reference range of 0.33 to 1.35% (0.020 to 0.102 x 10(9) basophil s/L) for the mAb-based method. These data would recommend mAb-based ba sophil counting as a valuable tool for instrument evaluation. However, an observed bias of 0.09% against the manual differential suggests th at modifications are necessary before this technique can be considered as new reference. method. (C) 1996 Wiley-Liss, Inc.