The indirect haemagglutination assay (IHA) is a simple serological test that can be used to detect antibodies raised by humans to Burkholderia pseudomallei, the cause of melioidosis. The IHA is currently the most common test used worldwide to quantify the human antibody response to B. pseudomallei. It has been used extensively during serosurveys, but it should be noted that the diagnostic sensitivity and specificity of the IHA in regions endemic for melioidosis are low because background seropositivity in the healthy population is high.