Comparison of a rapid field immunochromatographic test to expert microscopy for the detection of Plasmodium falciparum asexual parasitemia in Thailand

Wongsrichanalai, Chansuda; Chuanak, Niphon; Tulyayon, S; Thanoosingha, Nichapat; Laoboonchai, Anintita; Thimasarn, Krongthong; Brewer, Thomas G.; Heppner, D. Gray

doi:10.1016/s0001-706x(99)00040-6

Cited by 50 publications

(34 citation statements)

References 27 publications

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“…It is not clear why a small number of specimens with parasitemias Ͼ5,000 parasites/l tested falsely negative, although this observation is not without precedent in either HRP-2-based assays (4,10,15,19,22,28,39) or MRDD assays that exploit other malarial antigens (18,19,27). While the number of specimens with false-negative results and high levels of parasitemia was small (Ͻ1.0% for each prototype), it is an area of continuing concern and suggests the interaction of other factors that may influence test outcome for a small subpopulation of symptomatic patients.…”

Section: Discussionmentioning

confidence: 99%

Devices for Rapid Diagnosis of Malaria: Evaluation of Prototype Assays That Detect Plasmodium falciparum Histidine-Rich Protein 2 and a Plasmodium vivax -Specific Antigen

et al. 2003

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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 Giemsastained 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/l, with a sensitivity of 83% for parasite densities of <500/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/l, 92% for parasite densities of 1,001 to 5,000/l, 94% for parasite densities of 501 to 1,000/l, and 55% for parasite densities of 1 to 500/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.The limitations associated with diagnostic microscopy are well documented. These limitations have fostered the development of nonmicroscopic alternatives for the diagnosis of malaria (1,3,6,11,20,21,23,26,36). Devices for the rapid diagnosis of malaria (MRDDs [malaria rapid diagnostic devices]) emerged in the past decade to meet the need for a reliable diagnostic adjunct to microscopy in the clinical setting (40). Timely, accurate diagnosis has the potential to greatly facilitate the provision of appropriate therapeutic interventions, and as the MRDD technology matures, these devices will have a pivotal role in malaria control initiatives.The leading MRDD technology is the immunochromatographic strip (ICS) format, into which antigen-capture immunoas...

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Section: Discussionmentioning

confidence: 99%

Devices for Rapid Diagnosis of Malaria: Evaluation of Prototype Assays That Detect Plasmodium falciparum Histidine-Rich Protein 2 and a Plasmodium vivax -Specific Antigen

et al. 2003

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“…In rural malaria clinics, or in instances where skilled microscopy cannot be readily employed or sustained, the ParaSight F test provides an acceptable aid to the diagnosis of malaria in symptomatic patients at risk for P. falciparum infection. A quick and accurate diagnostic test for P. falciparum would facilitate early intervention and appropriate patient management (4,17,18,32,34,35).…”

Section: Discussionmentioning

confidence: 99%

Malaria Rapid Diagnostic Devices: Performance Characteristics of the Para Sight F Device Determined in a Multisite Field Study

et al. 2001

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Microscopic detection of parasites has been the reference standard for malaria diagnosis for decades. However, difficulty in maintaining required technical skills and infrastructure has spurred the development of several nonmicroscopic malaria rapid diagnostic devices based on the detection of malaria parasite antigen in whole blood. The ParaSight F test is one such device. It detects the presence of Plasmodium falciparum-specific histidine-rich protein 2 by using an antigen-capture immunochromatographic strip format. The present study was conducted at outpatient malaria clinics in Iquitos, Peru, and Maesod, Thailand. Duplicate, blinded, expert microscopy was employed as the reference standard for evaluating device performance. Of 2,988 eligible patients, microscopy showed that 547 (18%) had P. falciparum, 658 (22%) had P. vivax, 2 (0.07%) had P. malariae, and 1,750 (59%) were negative for Plasmodium. Mixed infections (P. falciparum and P. vivax) were identified in 31 patients (1%). The overall sensitivity of ParaSight F for P. falciparum was 95%. When stratified by magnitude of parasitemia (no. of asexual parasites per microliter of whole blood), sensitivities were 83% (>0 to 500 parasites/l), 87% (501 to 1,000/l), 98% (1,001 to 5,000/l), and 98% (>5,000/l). Device specificity was 86%.

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“…1,2 Antigen-detection methods have recently been introduced for situations where reliable microscopy may not be available. In the case of infection with Plasmodium falciparum, these new rapid methods are based on detection of histidine-rich protein-2 (PfHRP-2; ICT Malaria Pf and ParaSight-F) [2][3][4][5][6][7] or parasite lactate dehydrogenase (pLDH; OptiMAL). [8][9][10][11] Species-specific pLDH isoforms have been used to develop a test for P. vivax (OptiMAL).…”

Section: Introductionmentioning

confidence: 99%

Performance of the Optimal Test for Malaria Diagnosis Among Suspected Malaria Patients at the Rural Health Centers

Iqbal

Muneer

Khalid

et al. 2003

The American Journal of Tropical Medicine and Hygiene

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Abstract. The OptiMAL test detects both Plasmodium falciparum and P. vivax malaria infections. In this study, we evaluated the performance of the OptiMAL test at the Basic Health Units (BHUs) and the District Health Quarter (DHQ) Center in rural villages of Punjab, Pakistan that provide minimal health services. Two sets of blood specimens obtained from 930 suspected malaria patients attending these BHUs were tested at BHUs and the DHQ Center by microscopy and the OptiMAL test. At the BHUs, 231 (25%) of the patients were positive by microscopy and 278 (30%) patients tested positive by the OptiMAL test. At the DHQ Center, microscopic analysis of a second set of specimens from the same patients confirmed the malaria infection in 386 (42%) patients and the OptiMAL test result was positive in 300 (32%) patients. To determine the performance of OptiMAL test at the BHUs and the DHQ Center, all data were compared with microscopy results obtained at the DHQ Center. The OptiMAL test results for P. falciparum at the BHUs were comparable to those of the OptiMAL test at the DHQ Center. However, the sensitivity, positive predictive value (PPV), and negative predictive value (NPV) of the OptiMAL test were considerably lower for P. vivax infections than for P. falciparum infections, irrespective of whether the test was performed at the BHUs or at the DHQ Center (P. falciparum: sensitivity ‫ס‬ 78-85%, PPV ‫ס‬ 89-97%, NPV ‫ס‬ 96-98%; P. vivax: sensitivity ‫ס‬ 61-76%, PPV ‫ס‬ 88-95%, NPV ‫ס‬ 90-93%). The OptiMAL test also detected a number of false-positive and false-negative results at both the BHUs and the DHQ Center. The false-positive results ranged from 1% to 2%; however, the number of false-negative results was much higher (BHUs: P. falciparum ‫ס‬ 22%, P. vivax ‫ס‬ 39%; DHQ Center: P. falciparum ‫ס‬ 15%, P. vivax ‫ס‬ 24%). In conclusion, these results, when combined with other advantages of the OptiMAL test, suggest that this test can be used by relatively inexperienced persons to diagnose malaria infection in rural areas where facilities for microscopy are not available.

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Comparison of a rapid field immunochromatographic test to expert microscopy for the detection of Plasmodium falciparum asexual parasitemia in Thailand

Cited by 50 publications

References 27 publications

Devices for Rapid Diagnosis of Malaria: Evaluation of Prototype Assays That Detect Plasmodium falciparum Histidine-Rich Protein 2 and a Plasmodium vivax -Specific Antigen

Devices for Rapid Diagnosis of Malaria: Evaluation of Prototype Assays That Detect Plasmodium falciparum Histidine-Rich Protein 2 and a Plasmodium vivax -Specific Antigen

Malaria Rapid Diagnostic Devices: Performance Characteristics of the Para Sight F Device Determined in a Multisite Field Study

Performance of the Optimal Test for Malaria Diagnosis Among Suspected Malaria Patients at the Rural Health Centers

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