Dataset Information

Laboratory-based performance evaluation of PIMA CD4+ T-lymphocyte count point-of-care by lay-counselors in Kenya.

ABSTRACT: CD4+ T-lymphocyte count testing at the point-of-care (POC) may improve linkage to care of persons diagnosed with HIV-1 infection, but the accuracy of POC devices when operated by lay-counselors in the era of task-shifting is unknown. We examined the accuracy of Alere's Pima™ POC device on both capillary and venous blood when performed by lay-counselors and laboratory technicians.In Phase I, we compared the perfomance of POC against FACSCalibur™ for 280 venous specimens by laboratory technicians. In Phase II we compared POC performance by lay-counselors versus laboratory technicians using 147 paired capillary and venous specimens, and compared these to FACSCalibur™. Statistical analyses included Bland-Altman analyses, concordance correlation coefficient, sensitivity, and specificity at treatment eligibility thresholds of 200, 350, and 500cells/?l.Phase I: POC sensitivity and specificity were 93.0% and 84.1% at 500cells/?l, respectively. Phase II: Good agreement was observed for venous POC results from both lay-counselors (concordance correlation coefficient (CCC)=0.873, bias -86.4cells/?l) and laboratory technicians (CCC=0.920, bias -65.7cells/?l). Capillary POC had good correlation: lay-counselors (CCC=0.902, bias -71.2cells/?l), laboratory technicians (CCC=0.918, bias -63.0cells/?l). Misclassification at the 500 cells/?l threshold for venous blood was 13.6% and 10.2% for lay-counselors and laboratory technicians and 12.2% for capillary blood in both groups. POC tended to under-classify the CD4 values with increasingly negative bias at higher CD4 values.Pima™ results were comparable to FACSCalibur™ for both venous and capillary specimens when operated by lay-counselors. POC CD4 testing has the potential to improve linkage to HIV care without burdening laboratory technicians in resource-limited settings.

SUBMITTER: Zeh C

PROVIDER: S-EPMC6118119 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

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Laboratory-based performance evaluation of PIMA CD4+ T-lymphocyte count point-of-care by lay-counselors in Kenya.

Zeh Clement C Rose Charles E CE Inzaule Seth S Desai Mitesh A MA Otieno Fredrick F Humwa Felix F Akoth Benta B Omolo Paul P Chen Robert T RT Kebede Yenew Y Samandari Taraz T

Journal of immunological methods 20170518

<h4>Background</h4>CD4+ T-lymphocyte count testing at the point-of-care (POC) may improve linkage to care of persons diagnosed with HIV-1 infection, but the accuracy of POC devices when operated by lay-counselors in the era of task-shifting is unknown. We examined the accuracy of Alere's Pima™ POC device on both capillary and venous blood when performed by lay-counselors and laboratory technicians.<h4>Methods</h4>In Phase I, we compared the perfomance of POC against FACSCalibur™ for 280 venous s ...[more]

PMID: 28529048

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Project description:Background:A key focus of health systems strengthening in low- and middle-income countries is increasing reach and access through task-shifting. As such models become more common, it is critical to understand the experiences of lay providers because they are on the forefront for delivering care services. A greater understanding would improve lay provider support and help them provide high-quality care. This is especially the case for those providing mental health services, as providing psychological care may pose unique stressors. We sought to understand experiences of lay counselors, focusing on identity, motivation, self-efficacy, stress, and burnout. The goal was to understand how taking on a new provider role influences their lives beyond simply assuming a new task, which would in turn help identify actionable steps to improve interventions with task-shifting components. Methods:Semi-structured interviews (n?=?20) and focus group discussions (n?=?3) were conducted with three lay counselor groups with varying levels of experience delivering a community-based family therapy intervention in Eldoret, Kenya. Thematic analysis was conducted, including intercoder reliability checks. A Stress Map was created to visualize stress profiles using free-listing and pile-sorting data collected during interviews and focus group discussions. Results:Counselors described high intrinsic motivation to become counselors and high self-efficacy after training. They reported positive experiences in the counselor role, with new skills improving their counseling and personal lives. As challenges arose, including client engagement difficulties and balancing many responsibilities, stress and burnout increased, dampening motivation and self-efficacy. In response, counselors described coping strategies, including seeking peer and supervisor support, that restored their motivation to persevere. At case completion, they again experienced high self-efficacy and a desire to continue. Conclusions:Findings informed suggestions for ways to incorporate support for lay providers into task-shifting interventions at initiation, during training, and throughout implementation. These include acknowledging and preparing counselors for challenges during training, increasing explicit attention to counselor stress in supervision, fostering peer support among lay providers, and ensuring a fair balance between workload and compensation. Improving and building an evidence base around practices for supporting lay providers will improve the effectiveness and sustainability of lay provider-delivered interventions.

Project description:BACKGROUND: Point-of-care CD4 testing can provide immediate CD4 reporting at HIV-testing sites. This study evaluated performance of capillary blood sampling using the point-of-care Pima™ CD4 device in representative primary health care clinics doing HIV testing. METHODS: Prior to testing, prescribed capillary-sampling and instrument training was undertaken by suppliers across all sites. Matching venous EDTA samples were drawn throughout for comparison to laboratory predicate methodology (PLG/CD4). In Phase I, Pima™ cartridges were pipette-filled with EDTA venous blood in the laboratory (N = 100). In Phase II (N = 77), Pima™ CD4 with capillary sampling was performed by a single operator in a hospital-based antenatal clinic. During subsequent field testing, Pima™ CD4 with capillary sampling was performed in primary health care clinics on HIV-positive patients by multiple attending nursing personnel in a rural clinic (Phase-IIIA, N = 96) and an inner-city clinic (Phase-IIIB, N = 139). RESULTS: Pima™ CD4 compared favourably to predicate/CD4 when cartridges were pipette-filled with venous blood (bias -17.3 ± STDev = 36.7 cells/mm3; precision-to-predicate %CV < 6%). Decreased precision of Pima™ CD4 to predicate/CD4 (varying from 17.6 to 28.8%SIM CV; mean bias = 37.9 ± STDev = 179.5 cells/mm3) was noted during field testing in the hospital antenatal clinic. In the rural clinic field-studies, unacceptable precision-to-predicate and positive bias was noted (mean 28.4%SIM CV; mean bias = +105.7 ± STDev = 225.4 cells/mm3). With additional proactive manufacturer support, reliable performance was noted in the subsequent inner-city clinic field study where acceptable precision-to-predicate (11%SIM CV) and less bias of Pima™ to predicate was shown (BA bias ~11 ± STDev = 69 cells/mm3). CONCLUSIONS: Variable precision of Pima™ to predicate CD4 across study sites was attributable to variable capillary sampling. Poor precision was noted in the outlying primary health care clinic where the system is most likely to be used. Stringent attention to capillary blood collection technique is therefore imperative if technologies like Pima™ are used with capillary sampling at the POC. Pima™ CD4 analysis with venous blood was shown to be reproducible, but testing at the point of care exposes operators to biohazard risk related to uncapping vacutainer samples and pipetting of blood, and is best placed in smaller laboratories using established principles of Good Clinical Laboratory Practice. The development of capillary sampling quality control methods that assure reliable CD4 counts at the point of care are awaited.

Project description:IntroductionIn Ghana, initiation of Antiretroviral Therapy (ART) is recommended for all patients with an HIV diagnosis, regardless of CD4+ T-cell count. However, measurement of CD4 count remains an important metric for identifying patients with advanced HIV disease, and assessing a person's overall immune status, which informs the decision to offer opportunistic infection screening and prophylaxis. Access to CD4+ T cell count in rural health facilities remains a major challenge in Ghana and other resource-limited settings. This study aimed to validate the accuracy of the BD FACSPresto near-patient device for measurement of CD4 count and hemoglobin concentration against the FACSCount (CD4) and Sysmex (hemoglobin) diagnostic machines when operated in both a district hospital and rural laboratory, serving a network of health posts in Ashanti Region, Ghana.MethodologyIn the first phase of the study, patients were recruited from a district hospital, and both venous and capillary blood samples were tested using the FACSCount and Sysmex as reference tests and compared to results of the FACSPresto performed in the clinic laboratory at the district hospital. In the second phase, patients were recruited from both the hospital and from rural health clinics, and samples were tested using the FACSPresto at a rural laboratory. Sensitivity and specificity among samples categorized into different clinically relevant CD4 count ranges were calculated, along with correlation between the Presto and the reference measurements, and mean and relative bias with limits of agreement.ResultsThe FACSPresto was successfully operated in both clinical settings. A total of 59 samples in the first phase and 48 samples in the second phase were included. Positive bias was observed when comparing CD4 count measured by BD FACSPresto to FACSCount in the district hospital (bias = 44, LOA -72,160) and in the rural laboratory setting (bias = 74, LOA -96, 244). In addition, capillary blood samples were shown to give higher measures when compared to venous blood samples from the same participant. All results were statistically significant (p<0.05) apart from hemoglobin measurement in venous blood in the rural laboratory. Correlation coefficients were high for CD4 count measures and lower for hemoglobin measures.ConclusionOverall, the Presto gave higher estimates of CD4 count compared to FACSCount, and hemoglobin measurements were higher than from Sysmex. Samples of capillary blood in turn gave higher results for both measurements compared to venous blood, consistent with previous analyses. These findings should be considered when selecting CD4 count machines for use at the point of care, especially in remote areas where capillary blood sampling may be preferable, but are likely balanced by device's ease of use, portability, and ability to expand access to services. These results are some of the first to demonstrate the accuracy of the FACSPresto in West Africa and show that this device can be successfully operated in a very rural lab setting and may therefore assist to provide CD4 count and hemoglobin concentration measurement to populations in need.

Project description:INTRODUCTION:Effective point-of-care testing (POCT) is reliant on optimal specimen collection, quality assured testing, and expedited return of results. Many of the POCT are designed to be used with fingerstick capillary blood to simplify the blood collection burden. However, fingerstick blood collection has inherent errors in sampling. An evaluation of the use of capillary and venous blood with CD4 POCT was conducted. METHODS:Three different specimen collection methods were evaluated for compatibility using the Alere Pima CD4 assay at 5 HIV/AIDS healthcare sites in Dar es Salaam, Tanzania. At each site, whole blood specimens were collected from enrolled patients by venipuncture and fingerstick. Pima CD4 testing was performed at site of collection on venipuncture specimens (Venous) and fingerstick blood directly applied to a Pima CD4 cartridge (Capillary-Direct) and collected into an EDTA microtube (Capillary-Microtube). Venous blood was also tested at the laboratory by the reference CD4 method and Pima for comparison analysis. RESULTS:All three specimen collection methods were successfully collected by healthcare workers for use with the Pima CD4 assay. When compared to the reference CD4 method, Pima CD4 testing with the Capillary-Microtube method performed similarly to Venous, while Pima CD4 counts with the Capillary-Direct method were slightly more biased (-20 cells/?L) and variable (-229 to +189 cells/?L limit of agreement). Even though all three collection methods had similar invalid Pima testing rates (10.5%, 9.8%, and 8.3% for Capillary-Direct, Capillary-Microtube, and Venous respectively), the ability to perform repeat testing with Capillary-Microtube and Venous specimens increased the likelihood of acquiring a valid CD4 result with the Pima assay. CONCLUSIONS:Capillary blood, either directly applied to Pima CD4 cartridges or collected in an EDTA microtube, and venous blood are suitable specimens for Pima CD4 testing. The advantages of capillary blood collection in an EDTA microtube are that it uses fingerstick collection which mimics venous blood and allows extra testing without additional blood collection.

Dataset Information

Laboratory-based performance evaluation of PIMA CD4+ T-lymphocyte count point-of-care by lay-counselors in Kenya.

Publications

Laboratory-based performance evaluation of PIMA CD4+ T-lymphocyte count point-of-care by lay-counselors in Kenya.

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