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J Clin Microbiol. 2018 Nov 21. pii: JCM.01277-18. doi: 10.1128/JCM.01277-18. [Epub ahead of print]

The field performance and diagnostic accuracy of a low-cost instrument-free point-of-care CD4 test (VISITECT® CD4) performed by different health worker cadres among pregnant women.

Author information

1
Burnet Institute, 85 Commercial Road, Melbourne, VIC 3004, Australia Stanley.luchters@burnet.edu.au.
2
Department of Epidemiology and Preventive Medicine, Monash University, 99 Commercial Road, Melbourne, Australia.
3
International Centre for Reproductive Health (ICRH), Department of Obstetrics and Gynaecology, Ghent University, C. Heymanslaan 10, 9000 Gent, Belgium.
4
Empilweni Services and Research Unit, Department of Paediatrics & Child Health, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Fuel Road & Oudtshoorn Street, Johannesburg, South Africa.
5
Burnet Institute, 85 Commercial Road, Melbourne, VIC 3004, Australia.
6
Wits Reproductive Health and HIV Institute, Faculty of Health Sciences, University of the Witwatersrand, Hillbrow Health Precinct, 22 Esselen Street, 2001 Johannesburg, South Africa.
7
Omega Diagnostics Ltd, Omega House, Hillfoots Business Village, Alva, FK12 5DQ, Scotland, UK.
8
The Alfred Hospital and Department of Infectious Diseases, Monash University, 55 Commercial Rd, Melbourne, VIC 3004, Australia.

Abstract

BACKGROUND:

Measuring CD4 counts remains an important component of HIV care. The VISITECT® CD4 is the first-ever instrument-free low-cost point-of-care CD4 test with results interpreted visually after 40 minutes, providing a result of above or below 350 CD4 cells/mm3.

METHODS:

Field performance and diagnostic accuracy of the test was assessed among HIV-infected pregnant women in South Africa. A nurse performed testing at the point-of-care using both venous and finger-prick blood, and a counsellor and laboratory staff tested venous blood in the clinic laboratory (four VISITECT® CD4 tests/participant). Performance was compared to the mean CD4 count from duplicate flow cytometry tests on venous blood (FACSCalibur Trucount).

FINDINGS:

In 2017, 156 patients were enrolled, providing a total of 624 VISITECT® CD4 tests (468 venous and 156 finger-prick samples). Of 624 tests, 28 (4·5%) were inconclusive. Generalised Linear Mixed Modelling showed better performance of the test on venous blood (sensitivity=81·7%, 95%CI=72·3-91·1; and specificity=82·6%, 95%CI=77·1-88·1) than on finger-prick specimens (sensitivity=60·7%, 95%CI=45·0-76·3; and specificity=89·5%, 95%CI=83·2-95·8; p=0·001). No difference in performance was detected by cadre of health worker (p=0·113) or between point-of-care versus laboratory-based testing (p=0·108).

CONCLUSIONS:

Adequate performance of VISITECT® CD4 with different operators and at the point-of-care, and no need of electricity or instrument, shows the potential utility of this device, especially for facilitating decentralization of CD4 testing services in rural areas.

FUNDING:

Funding was provided by the Saving Lives at Birth partners and the Australian NHMRC Project Grant GNT1063725.

PMID:
30463898
DOI:
10.1128/JCM.01277-18
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