Erroneous Ortho ELT800/WS WBC in chronic lymphatic leukaemia

The underestimation of WBC by the Ortho ELT800/WS cell analyser in some cases of chronic lymphatic leukaemia has been investigated. Incorrect WBC was obtained on 44% of samples. WBC, smear cell count, lymphocyte cell volume, stage of disease and chemotherapy were studied in both discrepant and non-discrepant cases. The evidence suggested that low lymphocyte cell volume was the major cause of the anomaly. The relationship of small lymphocyte cell volume to increased cell density is also discussed.