Deviation in White Blood Cell Count Measurement between WNR and WDF Channels on an Automated Hematology Analyzer XN-3000: A Case Report

BACKGROUND: At present, complete blood count (CBC) testing is one of the most common clinical tests. The XN-3000 used in our hospital utilizes the principles of impedance and semiconductor laser flow cytometry, which contains two types of leukocyte fractionation methods: White cell nucleated (WNR) and white cell differential (WDF) channels. CASE PRESENTATION: Herein, we present the case of a 63-year-old male patient who was admitted to our hospital for the treatment of non-small cell lung cancer (T4N3M1 [LYM, HEP, and OSS]). Biochemical data showed abnormal liver function and anemia. WNR results showed poor leukocyte and debris fractions compared with WDF results, and leukocyte counts were different between the two channels. However, the poor fractionation of the leukocyte and debris fractions in the WNR was resolved at the twofold dilution stage. To investigate the cause of the problem, precipitates affecting the  WNR measurement were visually checked. Consequently, insoluble precipitates were observed in the WNR mixture of the specimen of the patient. In our hospital, we measure 1200 CBCs/day and very rarely encounter abnormal specimens such as in the presented case. Normally, leukocyte counts are reported in priority to those measured by the WNR channel; however, in this case, the switching function was effective in giving priority to WDF  count  results because of the appearance of abnormal WNR plots. However, a system that can promptly confirm events when results are reported is necessary. CONCLUSION: We very rarely encounter abnormal specimens such as in the presented case. Normally, leukocyte counts are reported in priority to those measured by the WNR channel; however, in this case, the switching function was effective in giving priority to WDF count results because of the appearance of abnormal WNR plots. However, a system that can promptly confirm events when results are reported is necessary. When no clinical request for WDF measurement was made, the WNR scattergram must be confirmed, dilution measurement, if necessary, must be performed, or the WDF must be measured and reported to the clinician as useful criteria for diagnosis.