Evaluation of the FACSPresto, a New Point of Care Device for the Enumeration of CD4% and Absolute CD4+ T Cell Counts in HIV Infection

Makadzange, Tariro; Bogezi, Carola; Boyd, Kathryn; Gumbo, Anesu; Mukura, Dorinda; Matubu, Allen; Ndhlovu, Chiratidzo E.

doi:10.1371/journal.pone.0157546

Cited by 18 publications

(19 citation statements)

References 31 publications

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“…We found a slight overestimation of the absolute counts, similar to the one observed for other CD4-dedicated bench top instruments like the FACSCount [ 13 ]. Results from Dar es Salaam were also perfectly in line with FACSPresto results obtained in two other studies recently conducted in Africa [ 15 ; 16 ]. Correlation and clinical misclassification of patients based on capillary blood results were also in agreement with the previous studies [ 14 – 16 ].…”

Section: Discussionsupporting

confidence: 90%

“…Results from Dar es Salaam were also perfectly in line with FACSPresto results obtained in two other studies recently conducted in Africa [ 15 ; 16 ]. Correlation and clinical misclassification of patients based on capillary blood results were also in agreement with the previous studies [ 14 – 16 ]. An additional element in our study was the analysis of factors influencing final result, with identification of capillary blood collection, and the nurse performing the finger prick.…”

Section: Discussionsupporting

confidence: 90%

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Performance of FACSPresto Point-of-Care Instrument for CD4-T Cell Enumeration in Human Immunodeficiency Virus (HIV)-Infected Patients Attending Care and Treatment Clinics in Belgium and Tanzania

et al. 2017

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BackgroundCD4 T-cell counts are widely used to assess treatment eligibility and to follow-up HIV-infected patients. The World Health Organization prequalification of in vitro diagnostics program conducted a performance evaluation of the FACSPresto (BD Biosciences), a new point-of-care instrument to measure absolute CD4-T cell (CD4) counts and percentages in venous and capillary blood samples from HIV-infected patients.MethodsPatients were recruited in Belgium (200 patients) and in Tanzania (247 patients). Venous blood samples were analyzed in two nearby reference laboratories. In addition, nurses/technicians collected a capillary blood sample by finger prick directly into a FACSPresto CD4 cartridge. Assay precision was assessed on fresh blood and on external quality control samples. Trueness (bias) was assessed by comparing results from FACSPresto with the reference (single-platform FACSCalibur). Clinical misclassification was measured at 200, 350 and 500 cells/μL thresholds.ResultsIntra-assay precision was < 6%, and inter-assay < 8%. CD4 results from FACSPresto and reference method resulted in regression slopes of 0.99–1.11 using either venous or capillary blood. Correlation was better for venous than for capillary blood (minimum 0.97 vs 0.93 respectively). Capillary blood resulted in a larger bias than venous blood, with 24 and 83 cells/μL for absolute CD4 counts on capillary blood in Antwerp and Dar es Salaam respectively, vs 12 and 41 cells/μL on venous blood. Bias on CD4% was < 1% on both venous and capillary blood, and was proportionally better than for absolute CD4 counts. Clinical misclassification was in line with the average overestimation, showing a very good specificity, but sensitivity around 70–90%. The rejection rate was 11% on first reading, leading to 6% of all samples without final result after a second reading.ConclusionsThe FACSPresto performed very well on venous blood samples, and well on capillary blood samples.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionsupporting

confidence: 90%

Performance of FACSPresto Point-of-Care Instrument for CD4-T Cell Enumeration in Human Immunodeficiency Virus (HIV)-Infected Patients Attending Care and Treatment Clinics in Belgium and Tanzania

et al. 2017

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“…As far as FACSPresto method concerned, this technology performs well when compared to the reference method, since the mean bias is -8.1 cells/µl and 0.2%, for absolute count and CD4 percentage, respectively. These ndings are in line with previous studies that report similar results [31,32].…”

Section: Discussionsupporting

confidence: 94%

Assessment of two POC technologies for CD4 count in Morocco

Elharti

Abbadi

Bensghir

et al. 2020

Preprint

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Background : In the era of “test and treat strategy”, CD4 testing remains an important tool for monitoring HIV-infected individuals. Since conventional methods of CD4 count measurement are costly and cumbersome, POC CD4 counting technique are more affordable and practical for countries with limited resources. Before introducing such methods in Morocco, we decided to assess their reliability. Methods : In this study 92 blood samples from HIV-infected patients, were tested by PIMA and FACSPresto to derive CD4 count. Flow cytometry using FacsCalibur, was used as reference method for CD4 count comparison. Linear regression, Bland-Altman analysis were performed to assess correlation and agreement between these POC methods and the reference method. In addition, sensitivity and specificity, positive predictive value (PPV), negative predictive value (NPV) and misclassification percentage at 350 and 200 CD4 count thresholds; were also determined. Finally, because FACSPresto can also measure hemoglobin (Hb) concentration, 52 samples were used to compare FACSPresto against an automated hematology analyzer. Results : The coefficient of determination R 2 was 0.93 for both methods. Bland-Altman analysis displayed a mean bias of -32.3 and -8.1 cells/µl for PIMA and FACSPresto, respectively. Moreover, with a threshold of 350 CD4 count, PIMA displayed a sensitivity, specificity, PPV, NPV, were 88.57%, 94.12%, 91.18%, 92.31%; respectively. FACSPresto showed 88.23%, 96.23%,93.75% and 92.73%; respectively. Furthermore, the upward misclassification percentage was 8.57 and 5.88%, for PIMA and FACSPresto, respectively; whereas the downward misclassification percentage was 7.84% and 7.54%; respectively. With 200 cells/µl threshold, PIMA had a sensitivity, specificity, PPV and NPV of 83.33%, 98.53%, 93.75% and 95.71%, respectively. Regarding FACSPresto, sensitivity, specificity, PPV and NPV was 82.35%, 98.57%, 88.57% and 95.83%; respectively. Upward misclassification percentage was 5.56% and 5.88%, for PIMA and FACSPresto, respectively; whereas downward misclassification percentage was 4.41% and 4.29%; respectively. Finally, the hemoglobin measurement evaluation displayed an R 2 of 0.80 and a mean bias of-0.12 with a LOA between -1.75 and 1.51. Conclusion : When compared to the reference method, PIMA and FACSPresto have shown good performance, for CD4 counting. The introduction of such POC technology will speed up the uptake of patients in the continuum of HIV care, in our country.

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“…It will also reduce queues while reducing patient visits to health facilities as patients with immunodeficiency are prioritized and expected to reduce energy costs. Similar studies have been done in Kenya and many other countries using whole blood with EDTA anticoagulant and capillary blood to see the correlation [19][20][21][22][23]. The slight discrepancy between the individual results of BD FACSPresto ™ and other devices in this study was similar to those seen and accepted in other comparisons of conventional CD4 technologies.…”

Section: Discussionsupporting

confidence: 86%

Performance of the BD FACSPresto near to patient Analyzer in comparison with representative conventional CD4 instruments in Cameroon.

Sagnia¹,

Ghomsi²,

Gutiérrez³

et al. 2020

Preprint

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Background In the context of scaling the viral load in resource limited settings, following HIV infected patient’s adults and children with CD4+ T-lymphocyte count still very important in settings where the decentralization of treatment still has some challenges. Effective HIV monitoring in these resource-constrained settings needs affordable and reliable CD4+ T lymphocytes enumeration methods. We investigated the validity of a BD FACSPresto POC which is a dedicated system for enumeration that uses immunofluorescent technologies. In this study, we have assessed the sensitivity, specificity and correlation between most representative flow cytometry instruments present in Cameroon with more than 5000 CD4 T cells tests per year including FACSCalibur, FACSCount, and PIMA POC from Becton dinkinson and ALERE respectively. Methods 268 patients aged from 1 to 72 years old were enrolled and included in the study after inform consent. The BD FACSPresto POC CD4+ T cell technology was placed at CIRCB and operated by technician staff. HIV infected patients were from Chantal BIYA international reference Center (CIRCB), Centre de Sante Catholique de NKOLODOM, Centre de Sante Catholique de BIKOP and CASS de Nkolndongo – Yaounde We compared the accuracy of the BD FACSPresto and three existing reference technologies with more than 5000 tests per year like FACSCalibur, FACSCount and PIMA according to the number of CD4 test done per year and their repartition in the country. Bland – Altman method and correlation analysis were used to estimate mean bias and 95% limits of agreement and to compare the methods, including analysis by subgroup of participant gestational age. In addition sensitivity and specificity were determined. Statistical significance was set at p-value < 0.05 Results The BD FACSPresto POC system has excellent precision, accuracy and linearity for CD4+ T lymphocytes enumeration. Good correlations were obtained between the BD FACSPresto poc system and other single platform methods. Bland–Altman plots showed interchangeability between two machines mean bias BD-FACSPresto vs PIMA= -126,522(-161,221 to -91,822) BD-FACSPresto vs FACSCount= -38,708 (-58,935 to -18,482) and FACSPresto vs FACSCALIBUR= 0,791(-11,908 to 13,491). Mean difference with Absolute CD4+ T-lymphocyte values obtained from the BD FACSPresto system correlated well with PIMA, FACSCount, and FACSCalibur method with R 2 equal to 0.88, 0.92 and 0.968 respectively with P < 0.001 for all. The mean comparison between values obtained from BD FACSPresto with PIMA, FACSCount, and FACSCalibur using paired T test give P=0.17, P=0.5 and P=0.6 respectively meaning that there is no significant differences between values obtained with BD FACSPresto and PIMA, FACSCount or FACSCalibur CD4 enumeration machines. Further analysis revealed close agreement between all the three instruments with no significant difference between the forth methods (P=0.91) Conclusion This BD-FACSPresto POC system is a simple, robust and reliable system for enumeration of absolute and percentage of CD4+ T-lymphocytes especially suitable for remote areas with limited resources. Having one BD-FACSPresto POC system easy to use, should reduce the cost and thus increase and improved access to CD4 testing for HIV infected patients in resource-constrained countries. BD-FACSPresto POC CD4 will enable reduction in patient time and improve the overall quality of ART service count and may improve test access in remote areas. This technology can allow for greater decentralization and wider access to CD4 testing and ART

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Evaluation of the FACSPresto, a New Point of Care Device for the Enumeration of CD4% and Absolute CD4+ T Cell Counts in HIV Infection

Cited by 18 publications

References 31 publications

Performance of FACSPresto Point-of-Care Instrument for CD4-T Cell Enumeration in Human Immunodeficiency Virus (HIV)-Infected Patients Attending Care and Treatment Clinics in Belgium and Tanzania

Performance of FACSPresto Point-of-Care Instrument for CD4-T Cell Enumeration in Human Immunodeficiency Virus (HIV)-Infected Patients Attending Care and Treatment Clinics in Belgium and Tanzania

Assessment of two POC technologies for CD4 count in Morocco

Performance of the BD FACSPresto near to patient Analyzer in comparison with representative conventional CD4 instruments in Cameroon.

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