AEGiS-11IAC: Evaluation of a plasma separator card used with the rapid plasma reagin (RPR) test in the diagnosis of syphilis.

11th International AIDS Conference

Vancouver, British Columbia — July 7-12, 1996

Evaluation of a plasma separator card used with the rapid plasma reagin (RPR) test in the diagnosis of syphilis.

Int Conf AIDS 1996 Jul 7-12; 11:446 (abstract no. Pub.B.1049)
Ndinya-Achola JO, Kirisuah S, Mercer D, Dong S, Maitha G, Moses S; University of Nairobi, Nairobi, Kenya. Fax: 254-2-712007. E-mail: Plummer@bldgHSC.Lan1.uManitoba.CA.

Background and

OBJECTIVE: The importance of STD control in reducing HIV transmission is now recognized, but many developing countries face serious resource constraints for STD control. For example, shortages of needles and syringes, lack of transportation to central laboratories, and delays between blood drawing, testing and reporting of results means that syphilis testing and management is often not carried out effectively. Decentralization of testing should improve results, but standard tests require venipuncture and a centrifuge for efficient processing. The Program for Appropriate Technology in Health (PATH) has developed a plasma separator card which uses capillary (finger-prick) blood and does not require a centrifuge. The purpose of this study was to evaluate the performance of the test.

METHODS: Patients presenting to the Special Treatment Clinic in Nairobi, Kenya had finger-prick blood drawn by lancet and separated using the card. Plasma was tested for syphilis by the RPR test in the clinic. Venous blood was then drawn and centrifuged, and serum transported to a laboratory at the University of Nairobi for RPR testing. Positive tests were confirmed by Treponema pallidum hemaglutination antibody (TPHA) test. A true positive result was defined as a positive RPR test with titre of 1:2 or higher in the reference laboratory, together with a positive TPHA test.

RESULTS: Results are available on the first 134 patients and another 150 will be processed by the end of February 1996. The average patient age was 27.6 years and 67% were male. An adequate amount of plasma for RPR testing was collected on 97.8% of card separations. There was good acceptance of the procedure from both staff and clients. The overall syphilis seroprevalence in the reference laboratory was 25.4%. The card test had 85% sensitivity, 95% specificity and a positive predictive value of 85%. There were 5 positive cases missed by card testing, all with relatively low RPR titres (2 were 1:2, 2 were 1:4 and 1 was 1:8).

CONCLUSIONS: Syphilis testing using the plasma separator card appears to be a promising procedure. Evaluation will continue and further data evaluating a larger sample will be presented.

Keywords: AEGIS, Syphilis Serodiagnosis, Syphilis, Evaluation Studies, Sensitivity and Specificity, Plasma, Mass Screening, Antibodies, Bacterial, Blood Donors, Hemagglutination Tests, Diagnostic Errors, Seroepidemiologic Studies, Kenya, Human, Male, diagnosis, utilization, instrumentation, nursing, blood, methods, ICA11

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PubB1049