FIELD-EVALUATION OF A POLYMERASE CHAIN REACTION-BASED NONISOTOPIC LIQUID HYBRIDIZATION ASSAY FOR MALARIA DIAGNOSIS

In a blind field evaluation of a nonisotopic liquid hybridization assa y for detection of malaria parasites, 100 blood samples were tested fr om an area in which malaria is endemic; light microscopy was used as t he reference test, Sensitivity, specificity, and positive and negative predictive values of the hybridization assay were 100%, One sample th at was microscopy-negative and hybridization-positive was positive whe n reexamined, Another sample that was microscopy-positive and hybridiz ation-negative was negative at reexamination, The detection limit of t he test was greater than or equal to 0.0005% parasitemia, Four samples with mixed infections were misdiagnosed by microscopy as single-speci es infections, Four samples diagnosed as mixed infections by microscop y and single infection by the hybridization test had no evidence of a second Plasmodium species upon reexamination, The polymerase chain rea ction-based nonisotopic liquid hybridization assay was better than con ventional light microscopy in detecting low-grade parasite infection a nd offers an exceptional advantage for detecting mixed infections.