Which tests confirm diphtheria infection?

Which tests confirm diphtheria infection?

• A. PCR or culture of pharyngeal specimens
• B. Chest X-ray
• C. Antinuclear antibody testing
• D. Urinalysis only

Answer: (A)

Diphtheria infection is confirmed by directly identifying the organism and, if possible, its toxin production from the patient’s pharyngeal secretions. A throat or nasopharyngeal swab is cultured on selective tellurite-containing media to isolate Corynebacterium diphtheriae. Demonstrating toxin production, historically with an Elek test, or detecting the toxin gene by PCR, confirms the strain can cause disease. PCR for the tox gene is fast and sensitive and is widely used to confirm toxin-producing diphtheria. Other tests like chest X-ray, ANA testing, or urinalysis do not confirm diphtheria; they may help assess complications or other conditions but not the infection itself.

Diphtheria infection is confirmed by directly identifying the organism and, if possible, its toxin production from the patient’s pharyngeal secretions. A throat or nasopharyngeal swab is cultured on selective tellurite-containing media to isolate Corynebacterium diphtheriae. Demonstrating toxin production, historically with an Elek test, or detecting the toxin gene by PCR, confirms the strain can cause disease. PCR for the tox gene is fast and sensitive and is widely used to confirm toxin-producing diphtheria. Other tests like chest X-ray, ANA testing, or urinalysis do not confirm diphtheria; they may help assess complications or other conditions but not the infection itself.