Rapid Malaria Test Assessed for Field Use

Rapid diagnostic tests (RDT) for malaria infections could replace light microscopy in poor resource locations as their ease of use and accuracy are improved.

Although light microscopy (LM) is the gold standard for malaria diagnosis it is not available in many outlying health facilities and is time consuming, requires highly trained personnel and needs careful preparation and application of reagents to ensure quality results.

Scientists at the University of Gondar (Ethiopia) collected blood samples from 254 patients suspected to have malaria at a health center in Northwestern Ethiopia in the late malaria transmission-peak season from November 2011 to December 2011. The male to female ratio was 1.57:1, while the mean age of the participants was 21.4 years with an age range of 5 months to 75 years. Most of the participants were from rural areas of the district. The samples were examined immediately by light microscopy (LM) and the RDT.

The overall parasite positivity using LM was 104 (40.9%): 40 (15.7%) for Plasmodium falciparum, 58 (22.8%) for P. vivax and six (2.4%) had mixed infections. The CareStart RDT gave an overall parasite positivity of 100 (39.4%) with 50 (19.7%) for P. falciparum, 24 (9.5%) for P. vivax and 26 (10.2%) for mixed infections. Difference in detection of P. falciparum parasites using either the LM or the RDT was insignificant, but difference in detection of P. vivax using the LM and RDT was found to be significant.

The CareStart Malaria COMBO Test kit (Diasys Ltd.; New York, NY, USA) is a three-band RDT detecting histidine-rich protein 2 (HRP-2) and PAN- lactate dehydrogenase (pLDH) and results are obtained in 20 minutes. The test has an overall sensitivity of 95% and specificity of 94.2%. The sensitivity and specificity for mixed infections and non-falciparum malaria was slightly less. The authors concluded that the CareStart RDT test showed good sensitivity and specificity with an excellent agreement to the reference light microscopy. The RDT could therefore be used in place of microscopy, which in poor set-ups cannot be used routinely. The full study is available since in November 2012 in the Malaria Journal.

Related Links:
University of Gondar
Diasys Ltd.