What should you know about a PCR test for diphtheria?

Diphtheria can affect the throat, nose or skin. A clinician may collect a swab from the throat, a visible membrane or another affected site before antibiotics when possible. PCR searches that sample for genetic material linked to the bacterium. A detected result can support suspected diphtheria, but the test does not replace examination, toxin assessment or other laboratory work. A sore throat alone has many possible causes, so the result must be interpreted with the appearance of the throat, fever, exposure history and vaccination status.

Suspected diphtheria needs prompt medical assessment. Call the healthcare service before arrival and mention the concern, because staff may need to reduce exposure to others. Do not scrape a throat membrane or share cups, utensils or towels. Follow instructions about testing, monitoring and isolation. If treatment is prescribed, take the antibiotic treatment exactly as directed; close contacts may also need assessment, preventive medicine or vaccination advice. Keep childhood immunisation records available, especially when the schedule is incomplete or uncertain.

Seek emergency help immediately for difficulty breathing or swallowing, drooling, a rapidly enlarging neck, bluish lips, severe weakness, fainting or confusion. Obtain same-day medical advice for a sore throat with a thick grey or white coating, marked neck swelling, fever or recent contact with suspected diphtheria. Do not wait at home for PCR results when symptoms are severe.

Ask which site will be swabbed, whether samples were taken before antibiotics, when preliminary and final results are expected, and whether you need isolation or treatment before confirmation. Ask what close contacts should do and whether your immunisation record changes the plan.