Two-centre evaluation of the Abbott CD3500 blood counter.

The CD3500 blood counter (Abbott Laboratories) is a 33 parameter fully automated blood counter that produces a five part differential count with flagging of leucocyte abnormalities. In this evaluation excellent correlation between CD3500 and Coulter STKR blood counter was found for all red cell and platelet parameters on the 221 samples tested. Studies of carryover, mixing efficiency and precision also gave excellent results. There was a good correlation with manual 400 cell differential counts for neutrophils, lymphocytes, monocytes and eosinophils for the 468 samples compared. Correlation of CD3500 and manual basophil counts was poor. Normal samples stored at 4 degrees C and analysed while cold showed satisfactory stability for WBC, RBC, Hb, MCV and platelets for 48 h and a stable differential for 24 h. Correlation with the differential count produced by the Coulter STKS showed good correlation for neutrophils, lymphocytes, monocytes and eosinophils; correlation with STKS basophils was poor. False positive flagging rate varied between 8.9% (Band and/or IG) and 0.9% (NRBC) depending on the nature of the flag; 5.8% of samples exhibited two or more false positive flags. No significant breakdowns were encountered during the period of the evaluation. The scatterplot displays of laser light scatter produced by the instrument provide an interesting adjunct to conventional morphology.