The assay manufacturer cites a specificity of 99.95% and a sensitivity of 100% on serum [8]. An off-license, internal validation exercise was undertaken, testing whole saliva specimens from a reference population of individuals of known HIV serostatus on this assay: HIV-positive, n = 100; HIV status unknown but having standard contemporaneous HIV serology, n = 20 (serology was performed using the Abbott Architect selleck chemicals HIV Ag/Ab fourth-generation assay on the Abbott Architect ci8200 Integrated System; Abbott Diagnostics, Maidenhead, UK). There was 100% agreement between whole saliva results and HIV serostatus and/or the result of the
standard serology. This method was rolled forward into the emergency department, dermatology out-patient, and primary care arms of the HINTS study (the dermatology arm employing the TECAN RMP200 platform; Tecan UK Ltd, Reading, UK). A total of 3721 tests were undertaken using the Bio-Rad assay on oral fluid. There were 11 reactive results, of which four were confirmed to be true positives. This yielded a method-specific
test specificity of 99.81% [95% confidence interval (CI) 99.67–99.95%] with a positive predictive value in this population of 36% (prevalence of HIV in this population: 0.11%; 95% CI 0.05–0.33%). During this phase, patients across all four settings were asked to participate in a questionnaire study (see [7] for details of the recruitment process and respondent characteristics). This survey demonstrated this website from clear support for oral fluid sampling. In response to the question ‘I would be happy providing the following sample for an HIV test’, 96% of 528 respondents agreed with ‘Saliva (spitting) with result in one week’ and 95% with ‘Mouth swab (like brushing teeth) with result in one week’, significantly more than for the other methods offered (‘Blood test with result in a week’, 89% agreement, and ‘Fingerprick blood test with immediate result’, 90% agreement; p < 0.001). However, this methodology was labour intensive, with manual aliquotting
of oral fluid samples. The assay process time was 4 h. Batching of samples meant that the mean turn-around time was 8 days. The original specimen was whole saliva, collected in universal containers. This yielded a number of invalid results, because of contamination. We latterly employed the Oracol+ oral fluid collection device (Malvern Medicals, Worcester, UK) which resulted in cleaner samples, with fewer re-tests required. The limitations of the above test prompted an exercise to investigate the feasibility of developing a fully automated laboratory-based, oral fluid HIV test. An off-license evaluation exercise was undertaken using the Abbott Architect HIV Ag/Ab fourth-generation assay on the Abbott Architect ci8200 Integrated System (Abbott Diagnostics, Maidenhead, UK).