For the Mantoux TB test, how far below the elbow bend should the injection be placed intradermally?

For the Mantoux TB test, how far below the elbow bend should the injection be placed intradermally?

• A. 2 Inches
• B. 4 Inches
• C. 6 Inches
• D. 8 Inches

Answer: (B)

When giving a Mantoux test, place the intradermal injection on the inner forearm at a standard, easily accessible spot. The conventional distance is about four inches below the elbow bend. This location provides flat, relatively thin skin that makes a small, detectable wheal when the injection is done correctly, and it keeps the site away from the elbow crease where movement can distort readings. Four inches below the elbow is used for consistency across patients, so readings 48 to 72 hours later are comparable. Being too close to the elbow bend (closer than about two inches) can cause skin folds and movement to interfere with the wheal, while going farther down the forearm (six or eight inches) isn’t the standard site and can introduce variability in skin properties and reading accuracy.

When giving a Mantoux test, place the intradermal injection on the inner forearm at a standard, easily accessible spot. The conventional distance is about four inches below the elbow bend. This location provides flat, relatively thin skin that makes a small, detectable wheal when the injection is done correctly, and it keeps the site away from the elbow crease where movement can distort readings.

Four inches below the elbow is used for consistency across patients, so readings 48 to 72 hours later are comparable. Being too close to the elbow bend (closer than about two inches) can cause skin folds and movement to interfere with the wheal, while going farther down the forearm (six or eight inches) isn’t the standard site and can introduce variability in skin properties and reading accuracy.