According to CDC guidelines, what induration size is considered positive for persons born in high prevalence areas or IV drug users?

According to CDC guidelines, what induration size is considered positive for persons born in high prevalence areas or IV drug users?

• A. 5 mm
• B. 15 mm
• C. 10 mm
• D. 20 mm

Answer: (C)

A tuberculin skin test (Mantoux) uses induration size to judge infection, with cutoffs that vary by risk group. For people born in high TB prevalence areas or who are IV drug users, a 10 mm or larger induration is considered positive. This lower threshold reflects the higher likelihood of true infection in these groups, aiming to catch cases without missing them. Positive does not mean active disease; it indicates latent TB infection and calls for further evaluation to determine treatment needs. Higher thresholds (like 15 mm) are used for those with lower risk to reduce false positives, and a 5 mm cutoff is reserved for the highest-risk individuals (e.g., HIV, recent TB exposure). The 20 mm mark is not a standard CDC cutoff.

A tuberculin skin test (Mantoux) uses induration size to judge infection, with cutoffs that vary by risk group. For people born in high TB prevalence areas or who are IV drug users, a 10 mm or larger induration is considered positive. This lower threshold reflects the higher likelihood of true infection in these groups, aiming to catch cases without missing them. Positive does not mean active disease; it indicates latent TB infection and calls for further evaluation to determine treatment needs. Higher thresholds (like 15 mm) are used for those with lower risk to reduce false positives, and a 5 mm cutoff is reserved for the highest-risk individuals (e.g., HIV, recent TB exposure). The 20 mm mark is not a standard CDC cutoff.