[Evaluation of Sysmex XN-3000 for Detection of Schistocyte].

OBJECTIVE: Compared with the method of optical microscopy, to evaluate the accuracy of fragmented red cells(FRC) detection by Sysmex XN-3000. METHODS: A total of 111 samples were collected from patients diagnosed as thrombotic thrombocytopenic purpura, autoimmune disease, hematological disease, malignant tumor and health examination in our hospital from June 2019 to February 2021, including 74 cases in the case group and 37 cases in the healthy control group. All samples were detected by optical microscope and Sysmex XN-3000, respectively. ROC was used to evaluate the detection ability of Sysmex XN-3000 for schistocyte. Bland-Altman method was used to evaluate the consistency of the results of the two methods for detection of schistocyte, and Pearson correlation analysis was conducted for the difference of the results. RESULTS: The area under the ROC curve was 0.890(95% CI: 0.828-0.952, P<0.01). Sysmex XN-3000 count did not quantitatively agree with schistocyte counts by microscopy in the case group(mean of difference:-1.53, 95% limits of agreement: -8.78~5.72). There was a weak positive correlation between platelet count and the difference of analyzer and microscopic results (r=0.32,P<0.05). CONCLUSION: Sysmex XN-3000 can be used as a reference for qualitative determination of schistocyte. However, the sensitivity of Sysmex XN-3000 should be improved. It is still necessary to combine with manual microscopy. The quantitative results are not reliable now and cannot be used as a reference for monitoring the results of schistocyte in clinical patients after treatment.

Evaluation of Sysmex XN-3000 for Detection of Schistocyte / 中国实验血液学杂志

OBJECTIVE@#Compared with the method of optical microscopy, to evaluate the accuracy of fragmented red cells(FRC) detection by Sysmex XN-3000.@*METHODS@#A total of 111 samples were collected from patients diagnosed as thrombotic thrombocytopenic purpura, autoimmune disease, hematological disease, malignant tumor and health examination in our hospital from June 2019 to February 2021, including 74 cases in the case group and 37 cases in the healthy control group. All samples were detected by optical microscope and Sysmex XN-3000, respectively. ROC was used to evaluate the detection ability of Sysmex XN-3000 for schistocyte. Bland-Altman method was used to evaluate the consistency of the results of the two methods for detection of schistocyte, and Pearson correlation analysis was conducted for the difference of the results.@*RESULTS@#The area under the ROC curve was 0.890(95% CI: 0.828-0.952, P<0.01). Sysmex XN-3000 count did not quantitatively agree with schistocyte counts by microscopy in the case group(mean of difference:-1.53, 95% limits of agreement: -8.78~5.72). There was a weak positive correlation between platelet count and the difference of analyzer and microscopic results (r=0.32,P<0.05).@*CONCLUSION@#Sysmex XN-3000 can be used as a reference for qualitative determination of schistocyte. However, the sensitivity of Sysmex XN-3000 should be improved. It is still necessary to combine with manual microscopy. The quantitative results are not reliable now and cannot be used as a reference for monitoring the results of schistocyte in clinical patients after treatment.

Comparison between optical microscopy and the Sysmex XN-3000 for schistocyte determination in patients suspected of having schistocytosis.

BACKGROUND AND AIMS: Diagnosis of thrombotic microangiopathy (TMA) relies on microscopic schistocyte determination by an experienced microscopist. In addition, schistocytes can be found in non-TMA-related disorders such as thalassaemia. We aimed to compare the accuracy of the automated haematology analyser Sysmex XN-3000 for schistocyte detection, to that of the microscopy approach, in patients suspected of having schistocytosis. METHODS: Consecutive blood samples were collected between April 2016 and March 2017 at Siriraj Hospital, Mahidol University, Bangkok, Thailand. Specimens were collected from adults with suspected TMA or with thalassaemia trait and/or disease. All blood samples were examined by both microscopy and the analyser. Samples were considered to be positive for schistocytes (ie, schistocytosis) if they had a schistocyte count ≥1% by microscopy. The analyser's ability to determine schistocytosis was assessed by receiver operating characteristic (ROC) curve. Sensitivity, specificity, positive (PPV), and negative predictive value (NPV) of an appropriate cut-off point were calculated, with manual microscopy as the standard. Quantitative agreement in schistocyte counts between the two approaches was assessed using 95% limits of agreement, Bland-Altman plots, intraclass correlation coefficient, and concordance correlation coefficient. RESULTS: Ninety-seven blood samples (62 suspected TMA and 35 thalassaemia) were collected. ROC curve analysis of the analyser for determining schistocytosis showed an area under the curve of 0.803 (95% confidence interval, 0.689-0.917, P < 0.001). A cut-off point of 0.6% yielded 86.1% sensitivity, 77.8% specificity, 94.4% PPV, and 56.0% NPV. The automated schistocyte count did not quantitatively agree with schistocyte counts by microscopy, neither in all blood specimens (mean of difference: -1.09; 95% limits of agreement, -11.9 to 9.7) nor in the subgroups (TMA, -0.88; 95% limits of agreement, -6.60 to 4.84; thalassaemia, -2.4; 95% limits of agreement, -14.10 to 9.30). The differences in the estimation of fragmented red blood cells between the methods tended to increase at higher schistocyte counts. CONCLUSION: Sysmex XN-3000 can be used for qualitative measurement of schistocytosis, but should not be used as a quantitative tool for schistocyte counting. Improvements are needed before this analyser's schistocyte detection feature can be recommended for use in clinical practice.

Fragmented red blood cells automated measurement is a useful parameter to exclude schistocytes on the blood film.

INTRODUCTION:   The diagnosis of thrombotic microangiopathies (TMA) or disorders that may mimic their features remains difficult. Mechanical hemolytic anemia with the detection of shistocytes on the blood smear is a cornerstone finding to assess the diagnosis, but microscopic evaluation of shistocytes is still problematic with wide interobserver variations. Some of the latest generation automated blood cell counters (ABCC) propose an original quantitative approach of fragmented red cells (FRC), aiming to be equivalent to the microscopic count. This parameter has been poorly evaluated. METHODS:   To assess the predictive value (PV) of this test, we conducted studies comparing automated and microscopic counts of FRC/schistocytes, based on the analysis of thousands samples in four university hospitals and using the 2 ABCC currently available (Siemens ADVIA series, Sysmex XE-2100). RESULTS: Reference range for FRC was <0.3% for the ADVIA and <0.5% for the XE-2100. The presence of FRC below a threshold determined at 1% (ADVIA and XE-2100) had a negative PV close to 100% to exclude the presence of schistocyte on the blood smear, but in relationship with a poor PV value. CONCLUSIONS: Our study validated the utility of the immediately available FRC parameter on ABCC to exclude schistocytes and the diagnosis of TMA.