Utilization of used human immunodeficiency virus ELISA microplates & surplus reagents for HIV antibody testing.

Used non-competitive enzyme-linked immunosorbent assay (ELISA) microplates were washed and reused to test samples and positive and negative controls, utilising the surplus reagents provided with the kit, which otherwise would have been discarded as useless after the entire 960 test kit had been utilized. These surplus reagents could be used for additional 220 tests over and above the recommended 960 tests per kit. A total of 839 unknown serum samples, 54 negative controls and 36 positive controls were tested using both washed and fresh (new) ELISA plates simultaneously. The optical density (OD) value of the control sera was within the prescribed limits in both the methods and 15 samples were found to be positive for HIV antibodies by the fresh plates whereas the washed plates showed 18 samples to be positive for HIV antibodies. None of the samples positive by fresh plates were negative by washed plates.