Typhoid in the modern era
The microbiology laboratory has made great strides in introducing clinically useful diagnostics over the past couple of decades, particularly in recent years with the development of molecular assays that ‘narrow the gap’ and provide early diagnoses.
While introducing new tests, it has also been important to evaluate and discard old tests that may not contribute greatly to patient outcomes. One such test that has come under the spotlight is the classic Widal agglutination test in the diagnosis of typhoid.
The Widal test, developed by George Fernand Widal in 1896, uses a suspension of killed Salmonella typhi as antigen to detect agglutinating antibodies to somatic O antigens and flagellar H antigens present in serum of typhoid patients. There are many reasons for its lack of clinical utility.
Antibodies are not present in the acute illness and take time to develop....