Use of a rapid test and an ELISA for HIV antibody screening of pooled serum samples in Lubumbashi, Zaire

Pools with a size of 3 and 5 were prepared by mixing one HIV confirmed HIV-1 seropositive serum with either 2 or 4 HIV seronegative sera at the Regional HIV Laboratory in Lubumbashi, Zaire. These pools were assessed in a blind fashion by ELISA (Vironostika anti-HTLV-III microELISA system, Organon Technika). Similarly constituted pools of 3 samples were assayed by a rapid test with visual reading (HIVCHEK 1 + 2, Dupont de Nemours). With the HIVCHEK, pooling was achieved on the test device itself by dropping consecutively 3 different serum samples on the devices's membrane. After the last serum was soaked in, wash fluid and conjugate were added. Results of the pooling experiments were compared with testing sera individually. The ELISA results from pools and from individual tested samples matched completely if, and only if, the final dilution of individual samples in the reagent medium was the same as recommended by the manufacturer for testing of individual samples. With the HIVCHEK a sensitivity of 99-100% was obtained with pooled sera. Both approaches seemed sensitive enough to enable their use for screening of blood donors and patient management, but a prospective study to validate these preliminary results is necessary