Comparison of two assays for detection of HIV antibodies in saliva

Abstract

The presence of HIV antibodies was screened in 241 paired samples of serum and saliva from seronegative subjects with risk factors for human immune deficiency virus (HIV) infection (n=99), asymptomatic and symptomatic HIV-seropositive patients (n=104) and healthy blood donors (n=38) as negative controls, in order to assess the reliability of two saliva tests for the detection of HIV antibodies. These results were confirmed by Western blot. The saliva samples were collected using an oral device (Salivette) maintained in the lateral gingival fold until the individual perceived that it was becoming less rigid due to hydration with saliva. The two tests were a rapid one (Test Pack) and a conventional one (GACELISA). The results for antibody detection in saliva show 99 % specificity and 99 % sensitivity for the rapid test versus 100 % sensitivity and 81 % specificity for the conventional test. All results for the saliva samples which were positive in the rapid test were confirmed by Western blot (WHO criteria), and there were no indeterminate Western blot results among the samples which were false-positive in the conventional enzyme immunoassay. No statistically significant differences were observed between the absorbance values of HIV-infected symptomatic and asymptomatic patients. The correlation for the results of the HIV-antibody analysis in the paired sera was 98 %. This method of saliva sampling in combination with a rapid and sensitive test for HIV-antibody detection may be applicable in studies conducted with limited technical resources or insufficiently trained health personnel or where blood sample collection is difficult.