The effect of anticoagulants in blood collection tubes on Plasmodium falciparum transmission in direct membrane feeding assays.

BACKGROUND: Direct membrane feeding assays assess the transmission potential of malaria-infected individuals using whole blood collected in anticoagulant vacutainers. METHODS: The potential inhibitory effect of four commonly used anticoagulants on gametocyte infectivity to mosquitoes was assessed in standard membrane feeding assays with cultured Plasmodium falciparum. RESULTS: Infection burden in mosquitoes was significantly reduced when blood was collected in sodium citrate and EDTA. Transmission was highest when blood was collected in lithium heparin and sodium heparin, although a concentration-dependent inhibition of mosquito infection was also observed. CONCLUSIONS: Although anticoagulants can reduce transmission efficiency, lithium heparin and sodium heparin are the best anticoagulants for evaluating malaria transmission.