What is the correct dose for a PPD test?

What is the correct dose for a PPD test?

• A. 0.1 mL
• B. 0.2 mL
• C. 0.5 mL
• D. 1 mL

Answer: (A)

Tuberculin skin testing uses a very small intradermal dose to elicit a localized immune response. The standard amount is 0.1 mL of purified protein derivative (5 tuberculin units), injected just under the skin to form a tiny wheal. This precise dose is essential for a reliable reading 48–72 hours later; using more than this amount can spread within the skin and distort the result, while a smaller or incorrect dose wouldn’t produce a proper induration. So the correct dose is 0.1 mL.

Tuberculin skin testing uses a very small intradermal dose to elicit a localized immune response. The standard amount is 0.1 mL of purified protein derivative (5 tuberculin units), injected just under the skin to form a tiny wheal. This precise dose is essential for a reliable reading 48–72 hours later; using more than this amount can spread within the skin and distort the result, while a smaller or incorrect dose wouldn’t produce a proper induration. So the correct dose is 0.1 mL.