Final answer:
The presence of Bordetella pertussis is initially tested using PCR techniques on a nasopharyngeal specimen taken from the patient. If the infection is in a later stage, an enzyme-linked immunosorbent assay (ELISA) can detect specific antibodies.
Step-by-step explanation:
To determine the presence of Bordetella pertussis, the bacterium that causes pertussis or whooping cough, several diagnostic tests can be done. During the early stages of infection, within the first two weeks, PCR techniques are used to diagnose B. pertussis directly from a nasopharyngeal specimen. This NP specimen is streaked onto Bordet-Gengou medium. However, it is crucial to transport the sample to the laboratory as quickly as possible to maintain the viability of the bacteria.
In the later stages of the infection, when PCR is less likely to detect the organism due to decreased bacterial load, immunological methods such as the enzyme-linked immunosorbent assay (ELISA) are employed for the detection of pertussis-specific antibodies. On the other hand, during the first month of infection, the diagnosis is generally confirmed using PCR.