title: Is serial testing required to diagnose imported malaria in the era of rapid diagnostic tests?
abstract: Exclusion of malaria traditionally requires three negative serial thick and thin blood films. However, many clinical laboratories now routinely perform rapid diagnostic tests (RDTs) in addition to blood films when malaria is suspected. We sought to determine whether serial testing is necessary in this setting. We examined 388 cases of malaria diagnosed during 1999-2010 at three laboratories in Melbourne, Australia. For each case, we ascertained whether the diagnosis was made on initial or follow-up testing. Nine cases (3.5%) were diagnosed after a negative initial blood film and RDT: 7 Plasmodium vivax, 1 P. ovale, and 1 P. falciparum. Of four case-patients with P. vivax in which clinical data were available, all had recent exposure to antimalarial medication. Our data suggest that among patients who have not received recent anti-malarial therapy, and when RDTs are performed and blood films are prepared, most malaria diagnoses are made by using the first set of tests.
authors.affiliation: Victorian Infectious Diseases Service, and Diagnostic Haematology Department, Royal Melbourne Hospital, Melbourne, Victoria, Australia. harper_janet@hotmail.com
authors.forename: Janet M
authors.initials: JM
authors.lastname: Pasricha
authors.forename: Surender
authors.initials: S
authors.lastname: Juneja
authors.forename: Joseph
authors.initials: J
authors.lastname: Manitta
authors.forename: Susan
authors.initials: S
authors.lastname: Whitehead
authors.forename: Ellen
authors.initials: E
authors.lastname: Maxwell
authors.forename: Wai-Keong
authors.initials: WK
authors.lastname: Goh
authors.forename: Sant-Rayn
authors.initials: SR
authors.lastname: Pasricha
authors.forename: Damon P
authors.initials: DP
authors.lastname: Eisen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008288:Malaria / Q000175:diagnosis* / Q000469:parasitology; D008875:Middle Aged