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AIDS. 1993 Dec; 7(12):1613-5.In 1990, Belgium, physicians enrolled 415 consecutive patients attending HIV reference centers in Antwerp, Brussels, and Ghent in a cross-sectional study designed to evaluate the clinical axis of the WHO staging system with and without the lymphocyte stratification proposed by Montaner el al. (that is, modified WHO staging system) (>1500, 1500- 1000, and <1000 cells x 1 million/l). They filled in a standardized questionnaire with all criteria of the WHO staging system. Laboratory personnel used standard hematology and flow cytometry techniques to determine absolute and CD4 lymphocyte counts. 80% of the patients were Caucasians. 46% of all patients were homosexual and 42% were heterosexual; 79.2% were men. Median CD4 lymphocyte counts fell in both staging systems as the stage of HIV infection increased. There were significant differences in median CD4 counts between stages of each staging system (p < .001). The modified WHO staging system's stage I was more sensitive at identifying patients with CD4 lymphocyte counts of more than 500 cells x 1 million/l than the WHO clinical stage 1 (83% sensitivity vs. 48% sensitivity). The positive predictive value of WHO clinical stage 4 and of the modified WHO staging system's stage IV for identifying people with CD4 lymphocyte counts of less than 200 cells x 1 million/l was quite high (79% and 80%, respectively). The researchers suggested that clinicians use stages 4 and IV as end-points is clinical trials in developing countries. Clinicians completing the questionnaire knew the patients' earlier CD4 lymphocyte count, which may have introduced a bias in the study. For example, they may have more thoroughly examined patients with low CD4 lymphocyte counts than those with normal counts. Nevertheless, the study's results indicated that either one of these systems may be a good alternative in developing countries to the technical equipment-dependent CD4 lymphocyte count-based HIV staging system used in developed countries. Cohort studies in developing countries would evaluate their prognostic value.
Lancet. 1993 Aug 7; 342(8867):379-80.Some HIV specialists propose alternative strategies of anti-HIV antibody screening to reduce costs. A western blot (WB) test confirming a positive anti-HIV antibody screening test is the time-honored strategy. WHO has guidelines on how to interpret WB results and how to handle indeterminate patterns. Tests for p24 antigen may identify HIV infection in those cases where the WB test fails to detect HIV infection during seroconversion. Alternative strategies proposed by authors of an earlier article to reduce HIV testing costs are flawed. For example, in 1 strategy, a positive result in the first test or ELISA and a negative result in a second test based on antigens or in another screening test based on a different principle leads to medical workers telling the person that he/she is HIV seronegative. Yet, the negative results of the second test may be due to seroconversion. Even though the first test should be as sensitive as possible, a subsequent negative test result should require another blood sample to test for p24 antigen. A second proposed strategy uses a competitive ELISA as the second test, but these assays cannot detect HIV-2 infection. The authors pooled the samples to illustrate cost saving, but pooling data loses sensitivity, especially for rapid tests. Virologists from Hospital Bichat-Claude Bernard in Paris, France, and earlier demonstrated the loss of sensitivity of rapid tests among sera from 9 patients in the early stage of HIV-1 seroconversion. They further believed that the manufacturer should determine reliability, sensitivity, and specificity. WHO did not take the above information into account when it addressed reducing the costs of HIV screening tests. Realistic diagnostic strategies are indeed needed in countries with few resources, but unreliable testing should not be the result of cost reductions.