Evaluation of the SD FK70 Malaria Ag Plasmodium vivax rapid diagnostic test in a non-endemic setting

Dijk

Bottieau

et al. 2009

Malar J

Self Cite

BackgroundThe SD FK80 P.f/P.v Malaria Antigen Rapid Test (Standard Diagnostics, Korea) (FK80) is a three-band malaria rapid diagnostic test detecting Plasmodium falciparum histidine-rich protein-2 (HRP-2) and Plasmodium vivax-specific lactate dehydrogenase (Pv-pLDH). The present study assessed its performance in a non-endemic setting.MethodsStored blood samples (n = 416) from international travellers suspected of malaria were used, with microscopy corrected by PCR as the reference method. Samples infected by Plasmodium falciparum (n = 178), Plasmodium vivax (n = 99), Plasmodium ovale (n = 75) and Plasmodium malariae (n = 24) were included, as well as 40 malaria negative samples.ResultsOverall sensitivities for the diagnosis of P. falciparum and P. vivax were 91.6% (95% confidence interval (CI): 86.2% - 95.0%) and 75.8% (65.9% - 83.6%). For P. falciparum, sensitivity at parasite densities ≥ 100/μl was 94.6% (88.8% - 97.6%); for P. vivax, sensitivity at parasite densities ≥ 500/μl was 86.8% (75.4% - 93.4%). Four P. falciparum samples showed a Pv-pLDH line, three of them had parasite densities exceeding 50.000/μl. Two P. vivax samples, one P. ovale and one P. malariae sample showed a HRP-2 line. For the HRP-2 and Pv-pLDH lines, respectively 81.4% (136/167) and 55.8% (43/77) of the true positive results were read as medium or strong line intensities. The FK80 showed good reproducibility and reliability for test results and line intensities (kappa values for both exceeding 0.80).ConclusionThe FK80 test performed satisfactorily in diagnosing P. falciparum and P. vivax infections in a non-endemic setting.

Section: Discussionsupporting

confidence: 68%

Test characteristics of the SD FK80 Plasmodium falciparum/Plasmodium vivax malaria rapid diagnostic test in a non-endemic setting

Dijk

Bottieau

et al. 2009

Malar J

Self Cite

“…Reported sensitivities for P. falciparum range from 87.5 to 99.0%, with one exception of 76.2% [3,[10][11][12][13][14][15][16]. However, the Immunoquick+4 did not reach the 95% sensitivity for parasite densities >100/µl recommended by the WHO [17].…”

Section: Discussionmentioning

confidence: 99%

“…However, the Immunoquick+4 did not reach the 95% sensitivity for parasite densities >100/µl recommended by the WHO [17]. For P. vivax, MRDTs targeting pan-pLDH show sensitivities from 33.5% and 62.0-95.0% [3,12,15,[18][19][20], compared to 46.0-93.0% [20] [20]. Previously, we demonstrated for a three-band HRP-2/pan-pLDH MRDT in a study design similar to the present one sensitivities for P. ovale and P. malariae of 76.3 and 45.2%, respectively [3].…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the Immunoquick+4 malaria rapid diagnostic test in a non-endemic setting

Dijk

Eur J Clin Microbiol Infect Dis

Vlieghe

et al. 2010

The aim of this retrospective study was to evaluate the Immunoquick+4 (BioSynex, Strasbourg, France), a three-band malaria rapid diagnostic test (MRDT) targeting histidine-rich protein-2 (HRP-2) and pan Plasmodium-specific parasite lactate dehydrogenase, in a non-endemic reference setting. Stored whole-blood samples (n=613) from international travellers suspected of malaria were used, with microscopy corrected by polymerase chain reaction (PCR) as the reference method. Samples infected by P. falciparum (n=323), P. vivax (n=97), P. ovale (n=73) and P. malariae (n=25) were selected, as well as 95 malaria-negative samples. The overall sensitivities of the Immunoquick+4 for the diagnosis of P. falciparum, P. vivax, P. malariae and P. ovale were 88.9, 75.3, 56.0 and 19.2%, respectively. Sensitivity was significantly related to parasite density for P. falciparum (93.6% versus 71.4% at parasite densities >100/µl and ≤100/µl, respectively) and P. vivax (86.8% versus 48.3% at parasite densities >500/µl and ≤500/µl, respectively). The Immunoquick+4 showed good reproducibility and reliability for both test results and line intensities. The Immunoquick+4 performed well for the detection of P. falciparum and P. vivax. Background

“…In previous evaluations of RDTs targeting Pv-pLDH, rare but consistent false positive Pv-pLDH test lines were observed among P. falciparum samples, especially at high parasite densities [2-4]. These observations are of concern as this limits the potential use of the Pv-pLDH directed RDTs, both in endemic and non-endemic settings.…”

Section: Introductionmentioning

confidence: 99%

Malaria rapid diagnostic tests: Plasmodium falciparum infections with high parasite densities may generate false positive Plasmodium vivax pLDH lines

Maltha

Cnops

et al. 2010

Malar J

Self Cite

BackgroundMost malaria rapid diagnostic tests (RDTs) detect Plasmodium falciparum and an antigen common to the four species. Plasmodium vivax-specific RDTs target P. vivax-specific parasite lactate dehydrogenase (Pv-pLDH). Previous observations of false positive Pv-pLDH test lines in P. falciparum samples incited to the present study, which assessed P. vivax-specific RDTs for the occurrence of false positive Pv-pLDH lines in P. falciparum samples.MethodsNine P. vivax-specific RDTs were tested with 85 P. falciparum samples of high (≥2%) parasite density. Mixed P. falciparum/P. vivax infections were ruled out by real-time PCR. The RDTs included two-band (detecting Pv-pLDH), three-band (detecting P. falciparum-antigen and Pv-pLDH) and four-band RDTs (detecting P. falciparum, Pv-pLDH and pan-pLDH).ResultsFalse positive Pv-pLDH lines were observed in 6/9 RDTs (including two- three- and four-band RDTs). They occurred in the individual RDT brands at frequencies ranging from 8.2% to 29.1%. For 19/85 samples, at least two RDT brands generated a false positive Pv-pLDH line. Sixteen of 85 (18.8%) false positive lines were of medium or strong line intensity. There was no significant relation between false positive results and parasite density or geographic origin of the samples.ConclusionFalse positive Pv-pLDH lines in P. falciparum samples with high parasite density occurred in 6/9 P. vivax-specific RDTs. This is of concern as P. falciparum and P. vivax are co-circulating in many regions. The diagnosis of life-threatening P. falciparum malaria may be missed (two-band Pv-pLDH RDT), or the patient may be treated incorrectly with primaquine (three- or four-band RDTs).