title: Antigen capture immuno-chromatographic strip format in detecting parasite-specific lactate dehydrogenase to diagnose malaria in nonimmune patients.
abstract: Several rapid diagnostic test devices (RDT) based on detection of malaria antigen in the whole blood were developed. OptiMal test the presence of parasite-specific lactate dehydrogenase (LDH) enzyme using three monoclonal antibodies was used. Two monoclonal antibodies were pan-specific and recognized all malaria species. The third one was specific only for Plasmodium falciparum. The parasite antigens were detected using an antigen-capture immunochromatographic strip format. One hundred-nine malaria positive and 730 malaria negative cases diagnosed by microscopy were included. 75/109 were P. falciparum 26 as P. vivax, 3 P. malariae and 5 mixed infection of P. falciparum & P. vivax. The RDT showed a low sensitivity (85%, 95% Confidence Interval [CI], 79-92%) with a much lower sensitivity in detecting species other than P. falciparum as well as in mixed infections. The sensitivity was 50% for less than 200 parasites/micro. The sensitivity of OptiMal for P. falciparum was 87% (95% CI, 79-94), 81% (95% CI, 66-96) for P. vivax, and failed with P. malariae. Mixed infections were misdiagnosed as Pfalciparum. The sensitivity of OptiMal was quite good in detecting both P. falciparum & P. vivax (98%; 95% CI, 97-99 & 100%; 95% CI, 100-100 respectively) and 99% (95% CI, 98-99) for all species. The positive and negative ratio for all malaria species was: (+LR = 62.3, -LR = 0.01); for P. falciparum (+LR = 38.9, -LR = 0.01) and for P. vivax (+LR = 0.8077/0, -LR = 0.2). The test value to assess drug resistance in post treatment days was discussed.
authors.affiliation: Department of Parasitology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
authors.forename: Amal M Abdul-Rasheed
authors.initials: AM
authors.lastname: El-Moamly
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan / Q000032:analysis* / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology*; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000032:analysis* / Q000276:immunology; D016778:Malaria, Falciparum / Q000175:diagnosis*; D016780:Malaria, Vivax / Q000175:diagnosis*; D010963:Plasmodium falciparum / Q000201:enzymology / Q000276:immunology; D010966:Plasmodium vivax / Q000201:enzymology / Q000276:immunology; D012680:Sensitivity and Specificity; D013045:Species Specificity
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007770:L-Lactate Dehydrogenase