Validation of a direct agglutination test prototype kit for the diagnosis of visceral leishmaniasis.

BACKGROUND

A freeze-dried antigen was developed with Leishmania (L.) infantum and used for the production of a prototype direct agglutination test kit for the laboratory diagnosis of visceral leishmaniasis (VL), called DAT-LPC. On this study the diagnosis validity of this prototype was performed.

METHODS

To evaluate the sensitivity and specificity 103 samples from Brazilian patients with VL and 110 samples from patients with other parasitic infections, and healthy subjects were assayed with DAT-LPC and DAT-KIT (Royal Tropical Institute, Amsterdam, NL). Additionally, the results of 103 samples of VL patients based on two agglutination tests were transformed in Log10 and correlated.

RESULTS

The DAT-LPC showed a sensitivity of 99.0%, specificity of 98.2% and diagnosis validity of 98.6%, which were similar to those found by the DAT-KIT (p > 0.05). Moreover, there was positive correlation between the positive titers obtained by DAT-LPC and by DAT-KIT (Spearman correlation coefficient of 0.75 p = 0.0001).

CONCLUSIONS

DAT-LPC showed thermal stability and diagnosis performance similar to those of the DAT-KIT. Our results suggest that DAT-LPC is a robust, simple, equipment-independent and efficient tool for the diagnosis of VL and should thus replace the IFAT as routine diagnostic test in the Brazilian public health system.