Optimizing dengue diagnosis by RT-PCR in IgM-positive samples: comparison of whole blood, buffy-coat and serum as clinical samples.

Dengue, a major public health problem in tropical and sub-tropical regions, is the most important arboviral disease of humans. Early diagnosis is very important on follow-up of infected patients, especially those at risk of the severe manifestations of this disease. Aiming at the improvement of the molecular diagnosis of these infections and due to the lack of studies that indicated the best sample for dengue virus detection by RT-PCR, viral detection by RT-PCR in blood, serum and buffy-coat of 75 IgM-positive serum samples for dengue was evaluated. Out of the 75 samples, 17 were positive for dengue using RT-PCR and from these samples, three were positive in the blood, 14 positive in the serum and eight positive in the buffy-coat. These results indicate that serum is the best clinical sample for RT-PCR amplification of dengue genomes.