Antigen Detection

An increasing number of pathogens can be detected directly in clinical samples by this means, eg. Cryptococcus, Haemophilus influenzae, Legionella, Neisseria meningitidis, Pneumocystis, and Streptococcus pneumoniae.

Antigen detection affords a more rapid diagnostic approach than cultural isolation. However, it does not allow for antimicrobial sensitivity testing and appropriate samples for culture should also be taken (although in many instances the same specimen suffices for both culture and antigen detection).

Usually the laboratory will take the initiative in performing antigen detection tests on samples received for microscopy and culture. If a clinician perceives a need for a particular test, the duty doctor is always on-call to discuss its availability either locally or at a reference centre (for example in the case of DNA probe or PCR technology).