4.3.2 Detecting the pathogen

Many rapid diagnostic tests detect the presence of infectious bacteria directly. Some tests can detect the presence of bacterial DNA, or antibiotic resistance genes in the sample, by a laboratory technique called polymerase chain reaction (PCR). This is known as molecular diagnostics which can be an extremely powerful diagnostic tool. Other tests rely on chemical reactions that cause a detectable colour change when bacteria (or a bacterial enzyme or product) are present in the sample.

The information these tests provide can vary. Some, such as the urinary tract infection (UTI) dipstick test, detect the presence of bacteria in a sample. Others, such as the Nordmann/Doret/Poirel test, can provide information on the bacteria’s susceptibility to antibiotics.