Many studies have reported hemocytometric changes in COVID-19 infection at admission and during the course of disease, but an overview is lacking. We provide a summary of the literature of hemocytometric changes and evaluate whether these changes may assist clinicians in diagnosing and predicting disease progression of COVID-19. Eighty-three out of 250 articles from December 2019 to 20 May 2020 were included from the databases, PubMed, Web of Science Core Collection, Embase, Cochrane and MedRxiv. Our review of the literature indicates that lymphopenia and an elevated neutrophil/lymphocyte ratio are the most consistent abnormal hemocytometric findings and that these alterations may augment in the course of time, especially in those with severe disease.

Background Due to increased travel from endemic countries, malaria occurs more frequently in non-endemic regions. It is a challenge for diagnostic laboratories in non-endemic countries to provide reliable results, as experience of staff is often limited to only a few cases per year. This study evaluated the diagnostic accuracy of the fully automated Sysmex XN-31 malaria analyzer in a routine diagnostic setting in a non-endemic region was evaluated. Methods Samples from 112 patients suspected for malaria were examined by the Sysmex XN-31 analyzer to determine the absolute count of malaria-infected red blood cells count (MI-RBC/µL). Microscopic examination of both Quantitative Buffy Coat capillary tubes and thick and thin blood films were used as reference methods. Limits of blank (LoB), detection (LoD) and quantification (LoQ) were investigated using an in vitro Plasmodium falciparum culture. Nine hundred twenty samples of patients with RBC abnormalities were included to determine which RBC abnormalities trigger indeterminate or false positive results. Results No false positive nor false negative results were obtained for the examined patient samples suspected for malaria. For 3% of samples an indeterminate result by the XN-31 was obtained. The Passing-Bablok regression line for diagnostic accuracy of the parasitaemia was y = 39.75 + 0.7892 × showing a positive bias of about 21% when comparing the MI-RBC results to microscopy. The LoB, LoD and LoQ were calculated to be 4.7, 5.9, and 19.0 infected RBC/μL, respectively. From the 920 abnormal RBC samples collected, 4.6% resulted in a false positive MI-RBC result and almost half of the samples produced indeterminate results. These results were related to increases in nucleated red blood cells, reticulocytes and other abnormal RBC morphologies such as sickle cells. Conclusions Based on the results, the XN-31 is a fast and reliable screening method in the detection and quantification of Plasmodium species in patients However, if an abnormal red blood cell morphology is present, the results of the XN-31 should be interpreted with caution as false positive results can be caused by interfering abnormal erythrocytes.

Introduction In 2015, Sysmex launched a new series of hematology analyzers (XN‐L Series) designed to fulfill the needs of niche laboratories in areas such as pediatrics, dialysis, neurology, and oncology while providing a compact solution. In this study, we evaluate the whole blood and body fluid modes of one of these analyzers, the XN‐350. Methods A total of 300 residual EDTA samples were measured on the XN‐350 in whole blood mode and the XN‐1000 to evaluate method comparison, flagging sensitivity, repeatability, reproducibility, linearity, carryover, and stability. In addition, 191 samples were obtained and processed in body fluid mode which included, cerebrospinal fluid (CSF), continuous ambulatory peritoneal dialysis (CAPD), ascites, synovial, and pleural fluid to perform method comparison, repeatability, reproducibility, linearity, limit of quantitation, and carryover studies. Results Strong agreement was shown between the XN‐350 and XN‐1000 for both whole blood and body fluid modes in results and flagging. Linearity results in both modes on the XN‐350 showed a high R2 value (>.99). For WBC, RBC, HGB, and PLT, the carryover results were well within the predetermined criteria of ≤0.5% for whole blood and ≤0.3% for CSF. Repeatability and reproducibility were acceptable for both modes, and there were no significant deviations present in stability for whole blood. In addition, there was high agreement in all body fluid types evaluated. Conclusion The performance of the XN‐350 is comparable to the XN‐1000 in both whole blood and body fluid modes, making it a reliable alternative to larger analyzers for smaller, niche laboratories.

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