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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
Performance evaluation of the Pima point-of-care CD4 analyser using capillary blood sampling in field tests in South Africa
Journal of the International AIDS Society, Volume 15, No. 1, Article 3, Year 2012
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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/mm 3; 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/mm 3) 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/mm 3). 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/mm 3). 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. © 2012 Glencross et al; licensee BioMed Central Ltd.
Available Materials
https://efashare.b-cdn.net/share/pmc/articles/PMC3310849/bin/1758-2652-15-3-S1.XLSX
Authors & Co-Authors
Glencross, Deborah Kim
South Africa, Johannesburg
University of the Witwatersrand Faculty of Health Sciences
South Africa, Parktown
National Health Laboratory Service of South Africa
Coetzee, Lindi Marie
South Africa, Johannesburg
University of the Witwatersrand Faculty of Health Sciences
South Africa, Parktown
National Health Laboratory Service of South Africa
Faal, Mamsallah
South Africa, Johannesburg
University of the Witwatersrand Faculty of Health Sciences
Masango, Martin
Zambia
Society for Family Health new Start Hct (hiv Counselling and Testing) Programme
Stevens, Wendy Susan
South Africa, Johannesburg
University of the Witwatersrand Faculty of Health Sciences
South Africa, Parktown
National Health Laboratory Service of South Africa
Venter, Willem Daniel François
South Africa, Johannesburg
University of the Witwatersrand Faculty of Health Sciences
Osih, Regina B.
South Africa, Johannesburg
University of the Witwatersrand Faculty of Health Sciences
Statistics
Citations: 83
Authors: 7
Affiliations: 3
Identifiers
Doi:
10.1186/1758-2652-15-3
e-ISSN:
17582652
Research Areas
Health System And Policy
Infectious Diseases
Maternal And Child Health
Study Design
Case-Control Study
Study Locations
South Africa