Dengue disease laboratory diagnostics in Thailand can be ordered on an individual basis and include dengue virus isolation, viral genome detection by reverse transcription polymerase chain reaction (RT-PCR), four-fold increases of paired sera (haemagglutination inhibition) or IgM >40 U or IgG increasing >100 U. Virological surveillance (virus isolation and serotyping by RT-PCR) is performed by the Department of Medical Science, especially before the outbreak season, which appoints a number of hospitals from around the country to act as sentinel sites. This evidence concerns the gene CD40LG and dengue disease.