Devices for rapid diagnosis of Malaria: evaluation of prototype assays that detect Plasmodium falciparum histidine-rich protein 2 and a Plasmodium vivax-specific antigen.
The ParaSight F test was developed as a pioneer industry effort in the large-scale, process-controlled production of a device for the rapid diagnosis of malaria. This device performed well in field settings but was limited to the detection of a single malaria species, Plasmodium falciparum. The ParaSight F+V assay advanced upon the ParaSight F test format by incorporating a monoclonal antibody directed against a proprietary Plasmodium vivax-specific antigen, in addition to the antibody directed against P. falciparum histidine-rich protein 2, which was used in the ParaSight F assay. The modified assay was developed to add the capability to detect P. falciparum and P. vivax in a single-test-strip format. The present study evaluated three distinct ParaSight F+V prototypes with samples from symptomatic patients in regions of Thailand and Peru where malaria is endemic. Over a 2-year enrollment period (1998 and 1999), a total of 4,894 patients consented to participation in the study. Compared with the results for duplicate microscopic examinations of Giemsa-stained blood smears as the reference diagnostic standard, each successive prototype showed substantial improvement in performance. The final ParaSight F+V prototype, evaluated in 1999, had an overall sensitivity for detection of asexual P. falciparum parasites of 98%. The sensitivity of the device was 100% for P. falciparum densities of >500 parasites/ micro l, with a sensitivity of 83% for parasite densities of </=500/ micro l. The specificity for the exclusion of P. falciparum was 93%. For P. vivax, the overall sensitivity was 87% for the final 1999 prototype. The sensitivities calculated for different levels of P. vivax parasitemia were 99% for parasite densities of >5,000/ micro l, 92% for parasite densities of 1,001 to 5,000/ micro l, 94% for parasite densities of 501 to 1,000/ micro l, and 55% for parasite densities of 1 to 500/ micro l. The specificity for the exclusion of P. vivax was 87%. The areas under the receiver operating characteristic curves for the diagnostic performance of the assay for the detection of P. falciparum and P. vivax were 0.8907 and 0.8522, respectively. These findings indicate that assays for rapid diagnosis have the potential to enhance diagnostic capabilities in those instances in which skilled microscopy is not readily available.
Forney
J Russ
JR
United States Military Academy, West Point, New York, USA. mj917@usma.edu
Wongsrichanalai
Chansuda
C
Magill
Alan J
AJ
Craig
Leslie G
LG
Sirichaisinthop
Jeeraphat
J
Bautista
Christian T
CT
Miller
R Scott
RS
Ockenhouse
Christian F
CF
Kester
Kent E
KE
Aronson
Naomi E
NE
Andersen
Ellen M
EM
Quino-Ascurra
Higinio A
HA
Vidal
Carlos
C
Moran
Kimberly A
KA
Murray
Clinton K
CK
DeWitt
Caroline Cady
CC
Heppner
D Gray
DG
Kain
Kevin C
KC
Ballou
W Ripley
WR
Gasser
Robert A
RA
D000818:Animals; D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan / Q000032:analysis*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D016778:Malaria, Falciparum / Q000175:diagnosis* / Q000469:parasitology; D016780:Malaria, Vivax / Q000175:diagnosis* / Q000469:parasitology; D018512:Parasitemia; D010568:Peru; D010963:Plasmodium falciparum / Q000302:isolation & purification; D010966:Plasmodium vivax / Q000302:isolation & purification; D011506:Proteins / Q000032:analysis*; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D013785:Thailand; D013997:Time Factors; D000099053:Histidine-Rich Glycoprotein
D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D011506:Proteins; D011933:Reagent Kits, Diagnostic; D000099053:Histidine-Rich Glycoprotein