October 1990, Volume 40, Issue 10

Letter to the Editor

HIV-CHEK SYSTEM; A RAPID TEST FOR THE DETECTION OF HIV-ANTIBODIES

Madam,

We evaluated the sensitivity and specificity of DuPont's HIV- CHEK System for the detection of an­tibodies against human immunodeficiency virus (HIV). HIV-CHIEK is a rapid and simple test1 as compared with the existing ELISA HIV- antibody techniques2 . Dupont’s HIV-CHEK uses recombinant HIV antigen which is adsorbed on a porous membrane. The HIV antibodies are captured by this antigen, presence of the antibodies is indicated by treatment with a protein A-gold conjugate and forms a red coloured-spot on the membrane. There is no real spot formation if the sample is negative for HIV antibodies. A total of 210 sera were tested; 150 negative and 60 HI V-antibody positive (positive on Western Blot). Of the total 210 samples in 16(7.6%) the serum was not absorbed througbthe porous material. All the negative samples were negative on HIV-CHEK i.e., there was no false positive. However in the panel of positive sera Hi V-CHEK failed to detect two samples (3.5%). Hence the sensitivity and specificity of the DuPont HIV-CHEK was 96.4% and 100% respectively. Well these are not bad scores for such a simple, rapid and visually read procedure. The problem which we faced was the non-absor­bance of serum through the porous membrane (in 7.6% of cases). This maybe due to the fact that most of our samples were frozen specimen. We disagree with the manufacturer for not shaking the frozen samples. We believe that all the frozen samples must be properly mixed before use. We feel that the HIV-CHEK system may be of good value in screening of fresh blood specimens (as the absorbance of serum through the porous material is not disturbed to a significant extent) at places where instru­ments for ELISA are not available and quick results are desired.

HIV-CHEK together with gelatin particle ag­glutination (Fujirebio) may solve our problem of screening the blood samples in the blood banks and in field testing3.

Farzal Anwer, Osman Yousuf, Manzoor Ahmed
WHO Collaborating Centre for AIDS Public Health Division, National Institute of Health, Islamabad.

REFERENCES

1. Josefsen, D. and Myrmel, H. Evaluation of a rapid test for detection of antibodies against human immunodeficiency virus (HIV). Acta­Pathol. Microbiol. Immunol. Scand., 1989; 97: 95.
2. Saxinger, C. and Gallo, R.C. Methods in laboratory investigation. Application of the indirect enzyme-linked immunosorbent assay microtest to the detection and surveillance of human t-cell leukemia-lymphoma virus. Lab. Invest., 1983; 49: 371.
3. Spielberg, F., Kabeya, C.M., Ryder, R.W., et al. Field testing and comparative evaluation of rapid, visually read screening assays for antibody to human immunodeficiency virus. Lancet, 1989; 1: 580.

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