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Intradermal injection

  • Procedure

An intradermal injection leaves a tiny amount just under the epidermis and raises a bleb; it is used for the tuberculin skin test and allergy tests.

Updated

What it is

The intradermal (ID) route places a very small amount into the dermis, just below the epidermis; of the parenteral routes it has the slowest absorption. That makes it suitable for sensitivity tests read on the skin, such as the tuberculin skin test (PPD or Mantoux) and allergy tests. The needle goes in almost flat against the skin, at 5–15°, bevel up. With correct technique a pale bleb forms. The site is not massaged or covered.

Indications

  • Tuberculin skin test.
  • Allergy tests.
  • Some vaccines, only when the product is approved for this route.

Contraindications and precautions

  • Choose skin free of lesions, rashes, moles or scars that would hide the reading.
  • Let the antiseptic dry completely before the injection.
  • After the injection the patient should not press on, rub or cover the site.

Equipment

  • Tuberculin syringe marked in tenths and hundredths.
  • Short 26 or 27 gauge needle.
  • Alcohol swab.
  • Clean gloves.
  • Sharps container.

Step by step (and why)

  1. Apply the rights and identify the patient — prevents wrong-substance and wrong-person errors.
  2. Choose the inner forearm, on skin free of lesions, rashes, moles or scars — they would hide the reading.
  3. Clean the site and let it dry completely — wet antiseptic irritates the skin.
  4. Stretch the skin and enter at 5–15° bevel up — the tip stays in the dermis.
  5. Advance only until the bevel is covered and inject slowly — a pale bleb should appear.
  6. If no bleb forms, report it per protocol — the test is not valid and is repeated at a new site at least 5 cm away.
  7. Withdraw without massaging, pressing or covering — massage spreads the fluid.
  8. Discard the needle and document site, time and reading date — the reading is done at 48–72 hours.

Complications

  • Injection too deep or too shallow (no bleb): the test is not valid and must be repeated.
  • Massaging or covering the site spreads the fluid and can alter the result.
  • Repeated tuberculin tests can boost later reactions.

Next step: when to call for help

  • If the tuberculin test is not read within 72 hours, a new test is scheduled.
  • Widespread hives, difficulty breathing or facial swelling: activate the emergency response.
  • Record the induration in millimetres (0 if there is none) and report it to the person who interprets the test.

Test yourself

Think of the answer, then tap the question to see it.

What angle is used for an intradermal injection?

5 to 15°, almost parallel to the skin, bevel up.

How do you know an intradermal injection was given correctly?

A pale bleb forms under the skin at the injection site.

What is measured when reading the tuberculin skin test?

The induration in millimetres, at 48–72 hours; redness is not measured.

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Connections

← All of nursing

Educational content for students; it does not replace your institution's protocols, supervised clinical training or a prescriber's order. Dose-calculation examples use made-up numbers: they are educational, not a clinical order.

Sources: Nursing Skills (Open RN), 18.4 Administering Intradermal Medications (Open RN, Chippewa Valley Technical College (LibreTexts), 2022); Nursing Skills (Open RN), 18.8 Checklists for Parenteral Medication Administration (Open RN, Chippewa Valley Technical College (LibreTexts), 2022); Clinical Testing Guidance for Tuberculosis: Tuberculin Skin Test (Centers for Disease Control and Prevention (CDC), 2025).

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