POLYMERASE CHAIN-REACTION AMPLIFICATION FROM PLASMODIUM-FALCIPARUM ONDRIED BLOOD SPOTS

We report a simple method for the polymerase chain reaction (PCR) ampl ification of whole blood samples collected on filter paper. The blood spot was used directly in the PCR after treatment with methanol. We ev aluated this assay using clinical samples collected from subjects in a Plasmodium falciparum vaccine trial and from samples collected during a hospital-based study in Thailand. Specimens prepared from hepariniz ed blood samples were successfully amplified following pretreatment wi th heparinase. Sensitivity was 100% when compared with thick blood fil m results in the vaccine trial (range = 4-60 parasites/mu l, median = 8/mu l) and 94.6% (range = 3-133,988 parasites/mu l, median = 616/mu l ) in the hospital study.