Evaluation of the malaria rapid diagnostic test SDFK90: detection of both PfHRP2 and Pf-pLDH

• Main Authors: Heutmekers Marloes, Gillet Philippe, Cnops Lieselotte, Bottieau Emmanuel, Van Esbroeck Marjan, Maltha Jessica, Jacobs Jan
• Format: Article
• Language: English
• Published: BMC 2012-10-01
• Series: Malaria Journal
• Subjects: Malaria; Plasmodium falciparum; Diagnosis; Rapid diagnostic test; Histidine-rich protein; <it>Plasmodium falciparum</it>-specific <it>Plasmodium</it> lactate dehydrogenase; Evaluation
• Online Access: http://www.malariajournal.com/content/11/1/359

<p>Abstract</p> <p>Background</p> <p>Rapid diagnosis of <it>Plasmodium falciparum</it> infections is important because of the potentially fatal complications. SDFK90 is a recently marketed malaria rapid diagnostic test (RDT) targeting both histidine-rich protein 2 (PfHRP2) and <it>P</it>. <it>falciparum</it>-specific <it>Plasmodium</it> lactate dehydrogenase (Pf-pLDH). The present study evaluated its diagnostic accuracy.</p> <p>Methods</p> <p>SDFK90 was tested against a panel of stored whole blood samples (n= 591) obtained from international travellers suspected of malaria, including the four human <it>Plasmodium</it> species and <it>Plasmodium</it> negative samples. Microscopy was used as a reference method, corrected by PCR for species diagnosis. In addition, SDFK90 was challenged against 59 <it>P</it>. <it>falciparum</it> samples with parasite density ≥4% to assess the prozone effect (no or weak visible line on initial testing and a higher intensity upon 10-fold dilution).</p> <p>Results</p> <p>Overall sensitivity for the detection of <it>P</it>. <it>falciparum</it> was 98.5% and reached 99.3% at parasite densities >100/μl. There were significantly more PfHRP2 lines visible compared to Pf-pLDH (97.3% <it>vs</it> 86.9%), which was mainly absent at parasite densities <100/μl. Specificity of SDFK90 was 98.8%. No lot-to-lot variability was observed (<it>p</it> = 1.00) and test results were reproducible. A prozone effect was seen for the PfHRP2 line in 14/59 (23.7%) <it>P</it>. <it>falciparum</it> samples tested, but not for the Pf-pLDH line. Few minor shortcomings were observed in the kit’s packaging and information insert.</p> <p>Conclusions</p> <p>SDFK90 performed excellent for <it>P</it>. <it>falciparum</it> diagnosis. The combination of PfHRP2 and Pf-pLDH ensures a low detection threshold and counters potential problems of PfHRP2 detection such as gene deletions and the prozone effect.</p>