Some organisms are present in infections in very low numbers, which may be undetectable with direct staining methods. These organisms may also be complex to recover with currently available culture methods.
Although non-culture antigen methods have been developed to address some of these difficulties (examples include direct fluorescent antibody [DFA] and enzyme immunoassay [EIA] methods), their sensitivity has not always been desirable.
Molecular methods offer the prospect of:
- Detecting nonviable organisms that did not survive transport
- Detecting organisms difficult/impossible to cultivate
- Detecting organisms present in low numbers
- Providing better detection capability than other non-culture methods
