Efficiency gains from the use of sample pooling technique: a theoretical example of dengue virus detection in vector

Testing large numbers of specimens for viral antigens, antibodies, requires a great deal of manpower, time and money. Therefore it would be useful if testing could be performed with the specimens pooled. However, how to establish the optimal number of specimens to be pooled to achieve the maximum efficiency while maintaining both sensitivity and specificity is a question that needs to be answered. In this study, we developed a mathematical model and procedure to resolve this problem. We estimated a saving rate of over 98% for an assumed infection rate of 1/10000 by testing the sample in pools of 100-101 specimens. The saving rate decreases with increasing infection rates, until there is probably no efficiency gain achieved for infection rates greater than 30%. Tests of infection in pooled mosquitoes were assumed to be free of viruses other than the dengue virus to interfere with detection. Heads of Aedes mosquitoes were first pooled and squashed, and the extract obtained was injected by intrathoracic inoculation into Toxorhynchites amboinensis, a biological amplifier of dengue antigen. Sensitivity was not reduced. Therefore, this pooling technique is useful for determining the optimal number of specimens in a pool, calculating an exact infection rate, and for identifying specific infected specimens in tests of a large number of samples showing low rates of infection in our theoretical example.