Rapid diagnosis of malaria by acridine orange staining of centrifuged parasites

A rapid diagnostic test for malaria based on acridine orange staining of centrifuged parasites in a microhaematocrit tube ('QBC' tube) was compared with the thick blood smear in 12 volunteers experimentally infected with Plasmodium falciparum, 408 residents of a malaria endemic area, and 1...

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Bibliographic Details
Published inThe Lancet (British edition) Vol. 1; no. 8629; p. 68
Main Authors Rickman, L S, Long, G W, Oberst, R, Cabanban, A, Sangalang, R, Smith, J I, Chulay, J D, Hoffman, S L
Format Journal Article
LanguageEnglish
Published England 14.01.1989
Subjects
Acridine Orange
Adolescent
Adult
Aged
Aged, 80 and over
Animals
Centrifugation
Child
Child, Preschool
Evaluation Studies as Topic
Humans
Infant
Malaria - blood
Malaria - diagnosis
Middle Aged
Parasitology - instrumentation
Parasitology - methods
Plasmodium falciparum - isolation & purification
Predictive Value of Tests
Staining and Labeling - methods
Time Factors
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Summary:A rapid diagnostic test for malaria based on acridine orange staining of centrifuged parasites in a microhaematocrit tube ('QBC' tube) was compared with the thick blood smear in 12 volunteers experimentally infected with Plasmodium falciparum, 408 residents of a malaria endemic area, and 180 hospital patients with suspected malaria. In the experimentally infected volunteers, the QBC tube test and the thick blood smear were comparable and the QBC tube could detect as few as 4 parasites/microliter blood. When used for mass screening in the field study, the test had a sensitivity of 70% for the diagnosis of malaria compared with 92% for a single thick blood smear. However, when used to diagnose malaria in hospital patients, the test detected as few as 3 parasites/microliter in 91 of 92 patients with asexual parasitaemia. For the three studies, the QBC tube was highly specific (98.4%), indicating malaria in only 8 of 487 subjects with negative blood films. The species of parasite was correctly identified in 77% of species. Processing the QBC tube was easier and much more rapid than was processing a thick blood smear, taking only 5 min for centrifugation and 5 min for examination. The QBC tube is not a substitute for the blood smear, but its speed and ease of use make it an important new tool for the diagnosis of malaria.
ISSN:0140-6736