Correction: Performance of the PointCare NOW System for CD4 Counting in HIV Patients Based on Five Independent Evaluations

Abstract

Introduction: Point-of-care (POC) CD4 testing can improve access to treatment by enabling decentralization and reducing patient loss-to-follow-up. As new POC CD4 technologies become available, their performance should be assessed before widespread deployment. This study reports the findings of five independent evaluations of the PointCare NOW CD4 system.Materials/Methods: Evaluations were conducted in Southern Africa (Mozambique, South Africa) and North America (Canada, USA). 492 blood samples (55 from HIV-negative blood donors and 437 from HIV-infected patients, including 20 children aged between 12 and 59 months) were tested with both the PointCare NOW and reference flow cytometry instruments. Assessment of bias, precision and levels of clinical misclassification for absolute and percent CD4 count was conducted.Results: PointCare NOW significantly overestimated CD4 absolute counts with a mean relative bias of +35.0%. Bias was greater in samples with CD4 counts below #350cells/ml (+51.3%) than in the CD4 .350cells/ml stratum (15.1%). Bias in CD4% had a similar trend with an overall relative mean bias of +25.6% and a larger bias for low CD4 stratum (+40.2%) than the higher CD4 stratum (+5.8%). Relative bias for CD4% in children was 26.8%. In terms of repeatability, PointCare NOW had a coefficient of variation of 11%. Using a threshold of 350cells/ml, only 47% of patients who qualified for antiretroviral therapy with reference CD4 testing, would have been eligible for treatment with PointCare NOW test results. This was 39% using a 200cells/ml threshold. Agreement with infant samples was higher, with 90% qualifying at a 25% eligibility threshold. Conclusion:The performance of the PointCare NOW instrument for absolute and percent CD4 enumeration was inadequate for HIV clinical management in adults. In children, the small sample size was not large enough to draw a conclusion. This study also highlights the importance of independent evaluation of new diagnostic technology platforms before deployment.

Field Evaluation of a Broadly Sensitive HIV-1 In-House Genotyping Assay for Use with both Plasma and Dried Blood Spot Specimens in a Resource-Limited Country

“…These parameters are routinely used in assessing treatment responses in resource-rich countries. HIVDR tests for patients on ART are not only important in monitoring individual patient treatment outcomes but also essential as public health tools in the routine assessment of the spread of drug-resistant variants at population levels (5,(17)(18)(19). Such data are vital in guiding a country's ARV drug regimen implementation strategy and in forecasting the need for new ARV drugs, especially in resource-limited settings where treatment options are limited (20)(21)(22).…”

A Simple Approach for Counting CD4+ T Cells Based on a Combination of Magnetic Activated Cell Sorting and Automated Cell Counting Methods

“…In the same report, the FDA-approved Cytospheres (CD4 Manual Count, Beckman Coulter, CA, USA) also repeat the same pattern with a high sensitivity yet low specificity, very low slope, and high absolute difference compared with the reference method at 99%, 32%, 0.58, and 58.6 cells/µL, respectively [39]. Conversely, a high positive bias leads to low sensitiity, typically illustrated by PointCare NOW (PointCare), also an FDA-approved platform [40], with a mean relative bias of 35% and a mean sensitivity of only 53% [41].…”

Head to head comparisons in performance of CD4 point-of-care assays: a Bayesian meta-analysis (2000–2013)

“…Because the ranges in the CD4 counts are wide, the mean bias is relative to the CD4 count, and should be reported as such. However, in our sample only two studies [29,30] reported the relative mean bias [27,30]. Future evaluations should report the relative mean bias, and more useful for comparison in future meta-analyses.…”