Carrier of diphtheria

This code identifies an individual who is a known carrier of Corynebacterium diphtheriae, the bacterium responsible for diphtheria, but is not currently experiencing active disease symptoms. These individuals harbor the bacteria, often in their nasopharynx, and can transmit it to others without showing signs of infection themselves.

Use this code for patients identified through laboratory testing (e.g., throat or nasal swab cultures) as positive for C. diphtheriae in the absence of clinical diphtheria. This is often relevant in public health surveillance, contact tracing following an active case, or screening of individuals in high-risk settings.

• Ensure laboratory documentation confirms the presence of C. diphtheriae and the absence of active diphtheria symptoms.
• Do not use this code for active diphtheria infection; refer to codes in Chapter 1 for active disease.
• Consider any associated exposure codes (e.g., Z20.818) if the carrier status is identified during contact tracing.