The laboratory diagnosis of typhoid fever

Abstract

Typhoid fever is a serious bacterial infection. Given its non-specific clinical presentation the laboratory diagnosis is critical.  This article discusses existing and potential diagnostic methods. Culture particularly of blood remains very important but needs to be optimised in terms of volume and timing. Existing serological tests including the outdated Widal test and other serological tests generally lack sufficient sensitivity and specificity, though newer serological tests detecting immunoglobulin A to lipopolysaccharide, haemolysin E and other novel antigens, hold potential. Multiplex polymerase chain reaction on blood following a short pre-enrichment step also appears to offer excellent sensitivity and specificity but may be more suitable for research studies at this stage. The limitations of blood culture as the existing reference method are noted, and alternatives discussed.