Towards a precise test for malaria diagnosis in the Brazilian Amazon: comparison among field microscopy, a rapid diagnostic test, nested PCR, and a computational expert system based on artificial neural networks

Table 5 Overall performance of microscopy and Optimal-IT in the discrimination of symptomatic malaria cases presenting with low parasitaemia.

Diagnostic method	*Plasmodium* species	Sensitivity	Specificity	PPV	NPV
Optimal-IT^®	Plasmodium non falciparum	76%*	100%	100%	75%
	P. falciparum	75%†	100%	100%	97%
	Plasmodium sp	76%*	100%	100%	88%
Microscopy	P. vivax	58%	100%	100%	88%†
	P. falciparum	63%	100%	100%	96%
	P. vivax + P. falciparum	59%	100%	100%	81%

Values represent data from patients with <500 parasites/μL of blood determined by light microscopy. Nested PCR was considered the gold standard. PPV, positive predictive value; NPV, negative predictive value. The results for the sensitivity, specificity, PPV and NPV obtained for each Plasmodium species were compared between the diagnostic methods using Fisher's exact test. *p < 0.01; †p < 0.05.

ISSN: 1475-2875