Diphtheria Diagnosis: Symptoms, Throat Culture, and Lab Tests

Clinical Evaluation

Doctors look for sore throat, difficulty swallowing, hoarseness, and a characteristic thick grayish membrane (pseudomembrane) covering the tonsils and throat.

Laboratory Confirmation

1. Throat swab culture: Sample from the throat is cultured for Corynebacterium diphtheriae.
2. Gram stain and culture: Identify the bacteria.
3. Toxin testing: If bacteria are found, further tests (toxin neutralization or PCR) determine if they produce diphtheria toxin.

Additional Tests

• Blood tests for diphtheria antitoxin antibodies (serology).
• Chest X-ray to assess pneumonia or airway involvement.

Accurate diagnosis requires clinical judgment and lab testing, as diphtheria can mimic tonsillitis or strep throat.