Paracheck-pf® Test Versus Microscopy in the Diagnosis of Falciparum Malaria in Arbaminch Zuria Woreda of South Ethiopia

BACKGROUND Malaria is a major cause of morbidity and mortality in Ethiopia. Rapid diagnostic tests such as Paracheck Pf are the major tools for falciparum malaria diagnosis as an alternative to microscopy in peripheral health facilities. The objective of this study was to evaluate the sensitivity and specificity of Paracheck Pf against microscopy for diagnosis of P.falciparum infection and observe the persistence of the antigen for an elongated period. METHODS Cross sectional study was undertaken in Arbaminch Zuria at Shele health center from October 2008 to January 2009. Paracheck-Pf versus microscopy comparison was done in conjunction with an artemisinin-based combination therapy efficacy monitoring for a period of 28 days. Standard microscopic procedures were done by experienced laboratory technicians and paracheck-Pf was performed in accordance with the manufacturer's instruction. RESULTS out of 1293 examined blood films, 400(31%) were found to be malaria positive. Considering microscopy as the gold standard, paracheck-pf showed sensitivity of 94.1 %( 95%CI: 89.9-98.3%) and specificity of 80.0% (95%CI: 67.6-92.4%). The positive and negative predictive values were 93.3 %( 95%CI: 88.8-97.8%) and 82.1% (95%CI: 70-94.1%), respectively. Comparing microscopy results 98.7 % (79/80), 60% (48/80), 48.1% (37/77), and 44.6 %( 33/74) were also found to be positive by paracheck-pf at days7, 14, 21, and 28, respectively. CONCLUSION Paracheck Pf® has a comparable diagnostic performance in detecting P. falciparum infections through the persistence of frequent false positivity is a limitation. Thus, this diagnostic test is not appropriate for monitoring of treatment effect.