Vol. 6, Issue 2, Part C (2024)

Aim: The aim of the present study was to compare the plasmodium lactate dehydrogenase (pLDH) and plasmodium falciparum specific histidine rich protein – 2 (pf HRP-2) based tests in rapid diagnosis of falciparum malaria.
Methods: This study was carried out in 80 children between age group of 1 month to 12 years admitted with suspected malaria to the children ward of Tata Main Hospital, Jamshedpur from August 2005 to October 2006. Blood was collected for thick and thin peripheral smear at the time of admission before starting treatment. pLDH based test OptiMAL as well as Pf HRP-2 based test Parachek-pf were also performed on the same sample. The sensitivity and specificity of pLDH based test OptiMAL and Pf HRP-2 based test parachek-pf were calculated using light microscopy of stained blood films as the gold standard. 
Results: In our study for the pf HRP-2 Based test parachek –pf the sensitivity and specificity was 96.5% and 86.3% respectively in comparison to microscopy. The positive and negative predictive values for the HRP-2 based test parachek-pf were 94.9% and 90.4% respectively.
In our study the sensitivity and specificity of pLDH based test OptiMAL were 87.9% and 100% respectively in comparison to microscopy. The positive and negative predictive values were 100% and 75.8% respectively. In both the tests the sensitivity was low at lower degree of parasitemia.
Conclusion: To conclude, light microscopy of well stained thick and thin blood films by a skilled microscopist remains the ‘Gold Standard’ for malaria diagnosis. Rapid diagnostic tests have a comparable sensitivity and specificity to microscopy at higher parasitemia. The results of these tests should be interpreted with caution when the parasite count is low.