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The XN-30 hematology analyzer for rapid sensitive detection of malaria: a diagnostic accuracy study.

ABSTRACT: BACKGROUND:Accurate and timely diagnosis of malaria is essential for disease management and surveillance. Thin and thick blood smear microscopy and malaria rapid diagnostic tests (RDTs) are standard malaria diagnostics, but both methods have limitations. The novel automated hematology analyzer XN-30 provides standard complete blood counts (CBC) as well as quantification of malaria parasitemia at the price of a CBC. This study assessed the accuracy of XN-30 for malaria detection in a controlled human malaria infection (CHMI) study and a phase 3 diagnostic accuracy study in Burkina Faso. METHODS:Sixteen healthy, malaria-naive CHMI participants were challenged with five Plasmodium falciparum-infected mosquitoes. Blood was sampled daily for XN-30, blood smear microscopy, and malaria qPCR. The accuracy study included patients aged >?3?months presenting with acute febrile illness. XN-30, microscopy, and rapid diagnostic tests (HRP-2/pLDH) were performed on site; qPCR was done in retrospect. The malaria reference standard was microscopy, and results were corrected for sub-microscopic cases. RESULTS:All CHMI participants became parasitemic by qPCR and XN-30 with a strong correlation for parasite density (R2?=?0.91; p?

SUBMITTER: Post A

PROVIDER: S-EPMC6543632 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

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The XN-30 hematology analyzer for rapid sensitive detection of malaria: a diagnostic accuracy study.

Post Annelies A Kaboré Berenger B Reuling Isaie J IJ Bognini Joel J van der Heijden Wouter W Diallo Salou S Lompo Palpouguini P Kam Basile B Herssens Natacha N Lanke Kjerstin K Bousema Teun T Sauerwein Robert W RW Tinto Halidou H Tinto Halidou H Jacobs Jan J de Mast Quirijn Q van der Ven Andre J AJ

BMC medicine 20190531 1

<h4>Background</h4>Accurate and timely diagnosis of malaria is essential for disease management and surveillance. Thin and thick blood smear microscopy and malaria rapid diagnostic tests (RDTs) are standard malaria diagnostics, but both methods have limitations. The novel automated hematology analyzer XN-30 provides standard complete blood counts (CBC) as well as quantification of malaria parasitemia at the price of a CBC. This study assessed the accuracy of XN-30 for malaria detection in a cont ...[more]

PMID: 31146732

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Project description:BackgroundThe Sysmex XN-V is derived from the new Sysmex XN series of human hematology analyzers. The main changes from the previously validated XT-2000iV analyzer include an optic-fluorescent analysis for platelets and nucleated RBC count.ObjectiveWe aimed to validate the Sysmex XN-V for canine blood according to American College for Veterinary Clinical Pathology and International Council for Standardization in Hematology recommendations.Materials and methodsCanine EDTA blood specimens and quality control material were analyzed on the Sysmex XN-V to evaluate imprecision, bias, linearity, a comparison with the XT-2000iV analyzer, interference effects, carry-over, and stability. We also verified previously established Sysmex XT-2000iV reference intervals (RIs).ResultsImprecision and bias were low (<5%) for most variables. Observed total error was lower than allowable total error for most measured variables except lymphocytes and monocytes. Visually determined linearity was excellent for all variables, except for lymphocytes. The correlation between the XN-V and XT-2000iV analyzers was high (>0.93) for all variables except MCHC and reticulocyte indices. Correlations between the Sysmex XN-V and manual differential counts were good for neutrophils and eosinophils, acceptable for lymphocytes, and fair for monocytes. Hemolysis, lipemia, and to a lesser extent icterus, had significant effects on measured hemoglobin concentration and associated variables. Carry-over was not visually observed for any variable. Changes in the Sysmex XN-V measurements after storage at 4℃ and 24℃ were similar to those described for the Sysmex XT-2000iV analyzer. The previously established Sysmex XT-2000iV RIs can be used to interpret results from the Sysmex XN-V analyzer for most variables except red blood cell distribution width and mean platelet volume.ConclusionsThe performance of the Sysmex XN-V analyzer was excellent and compared favorably with the Sysmex XT-2000iV analyzer.

Project description:Early and accurate diagnosis is critical in reducing the morbidity and mortality associated with malaria. Microscopy (MI) is the current diagnostic gold standard in the field; however, it requires expert personnel, is time-consuming, and has limited sensitivity. Although rapid diagnostic tests for antigen detection (RDTs) are an alternative to diagnosis, they also have limited sensitivity and produce false positive results in detecting recent past infection. The automated hematology analyzer XN-31 prototype (XN-31p) (Sysmex Corporation, Kobe, Japan) is able to identify plasmodium-infected erythrocytes, count parasitemia and perform complete blood-cell counts within one minute. The performance of the XN-31p in diagnosing malaria was evaluated and compared with real-time polymerase chain reaction (qPCR), MI and RDT in an endemic area of Colombia where Plasmodium falciparum and Plasmodium vivax are present. Acute febrile patients were enrolled from July 2018 to April 2019 in Quibdó, Colombia. Malaria diagnoses were obtained from MI and RDT in the field and later confirmed by qPCR. Venous blood samples in EDTA were processed with an XN-31p in the field. Sensitivity, specificity, positive/negative predictive values, and the likelihood ratios of positive and negative tests were calculated with respect to the results from qPCR, MI and RDT. The intraclass correlation coefficient (ICC) and Bland-Altman plot were used to evaluate the concordance in the parasitemia with respect to MI. A total of 1,754 subjects were enrolled. The mean age was 27.0 years (IQR 14-44); 89.6% were Afro-Colombians, 94.3% lived in urban areas and 0.91% were pregnant. With respect to qPCR, the XN-31p showed a sensitivity of 90% (95% CI 87.24-92.34) and a specificity of 99.83% (95% CI 99.38-99.98) in detecting Plasmodium spp.; both parameters were equivalent to those for MI and RDT. Using MI as the reference, the XN-31p showed a sensitivity of 98.09% (95% CI 96.51-99.08), a specificity of 99.83% (95% CI 99.4-99.98), an ICC of 0.85 (95% CI 0.83-0.87) and an average difference of - 3096 parasites/µL when compared with thick-smear MI and an ICC of 0.98 (95% CI 0.97-0.98) and an average difference of - 0.0013% when compared with thin-smear MI. The XN-31p offers a rapid and accurate alternative method for diagnosing malaria in clinical laboratories in areas where P. falciparum and P. vivax cocirculate.

Project description:BackgroundThe erythrocytic stage of Plasmodium falciparum parasites in humans is clinically important, as the parasites at this growth stage causes malarial symptoms. Most of the currently available anti-malarial drugs target this stage, but the emergence and spread of parasites resistant to anti-malarial drugs are a major challenge to global eradication efforts; therefore, the development of novel medicines is urgently required. In this study, the in vitro anti-malarial activity of five current anti-malarial drugs (artemisinin, atovaquone, chloroquine, mefloquine, and pyrimethamine) and 400 compounds from the Pathogen Box provided by the Medicines for Malaria Venture on P. falciparum parasites was characterized using the XN-30 analyzer. Furthermore, the outcomes obtained using the analyser were classified according to the parasitaemias of total and each developmental stages.ResultsThe growth inhibition rate and the half-maximal (50%) inhibitory concentration (IC50) of the five current anti-malarial drugs were calculated from the parasitaemia detected using the XN-30 analyzer. Respective strains and drugs presented strongly fitted sigmoidal curves, and the median SD at all tested concentrations was 1.6, suggesting that the variation in values measured with the analyser was acceptably low for the comparison of drug efficacy. Furthermore, the anti-malarial activity of the 400 compounds from the Pathogen Box was tested, and 141 drugs were found to be effective. In addition, the efficacy was classified into 4 types (Type I, parasites were arrested or killed without DNA replication; Type II, parasites were arrested or killed similar to Type I, and the parasitaemia was apparently decreased; Type III, parasites progressed to trophozoite without sufficient DNA replication; and Type IV, parasites were arrested at late trophozoite or schizont after DNA replication).ConclusionThe current study demonstrates that the XN-30 analyzer objectively, reproducibly, and easily evaluated and characterized the anti-malarial efficacy of various compounds. The results indicate the potential of the XN-30 analyzer as a powerful tool for drug discovery and development in addition to its use as an important diagnostic tool.

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The XN-30 hematology analyzer for rapid sensitive detection of malaria: a diagnostic accuracy study.

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The XN-30 hematology analyzer for rapid sensitive detection of malaria: a diagnostic accuracy study.

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