
Overview
This module describes how to give a shallow injection between the layers of the skin. Even though the technique is generic, this module will focus on Mantoux or Tuberculin Skin Testing (TST).
Indications
Sensitivity tests, such as TB tests and some allergy tests
Mantoux testing is indicated in children under 5 years of age, where TB is suspected
Contraindications
Damaged, infected, swollen, thickened, or scarred skin at the injection site
Contraindications to medication, such as Mantoux testing if the patient has previously had a severe reaction to tuberculin
Patient information and consent
Always verify your patient’s identity and obtain informed consent before proceeding.
How do I explain this procedure?
“This is a TB test. I need to inject a little bit of a test substance just under the skin of the forearm.”
What can my patient expect?
“This will only sting for a moment. You will see a small blister where I injected it. Over the next three days it may grow or shrink, and it will start to fade away after that.”
What is my patient’s role?
“Do not rub or scratch the area. I am going to mark the injection area with a pen. Please do not wash the mark off. Let me know if you suddenly feel short of breath or get a rash after I injected this. Return to the hospital or clinic if you see an open wound on your forearm after a day or two. You need to return in two or three days so that we can read this test.”
Preparation

Documentation
Patient notes
Equipment
Alcohol-based hand rub
- Sharps containerSharps container
If a sharps container is not within arm's length, use a kidney dish or other hard container to temporarily hold used sharps and to carry them to the sharps container for disposal.
Alcohol swab
1 ml syringe
Aspiration needle (ideally a blunt fill needle) and 25-27 G needle
Tuberculin (purified protein derivative)
Cotton ball and saline
Gloves if indicated
Site & Positioning
Use the left forearm and select a site 5-10 cm below the elbow joint, or roughly in the centre of the forearm. If the forearm cannot be used, the back of the shoulder may be used. Place the arm in extension. Ask a parent or assistant to restrain the child.
Procedure
Follow medical asepsis without gloves.
Perform hand hygiene. Do not routinely use gloves.
Draw up 0.1 ml of tuberculin.
Attach the 27 G needle to the syringe.
If the site is visibly dirty, clean with saline and a cotton ball.
With the non-dominant thumb, pull the skin of the site taut.
Use a 5-15° angle to insert the needle, bevel up, a few mm under the skin, as shallow as possible.
Inject the tuberculin. It should form a blister, or wheal.
Withdraw. Gently pat the area with a cotton ball if bleeding.
Dispose of medical waste safely.
Draw a circle around the site with a pen to mark it.
Perform hand hygiene.
Document the time and date you administered the tuberculin.
Advise the patient when to return.
Troubleshooting
There is no wheal.
You may have injected too deeply, in the subcutaneous space. Try again on the same forearm, 5 cm away from your original site. Carefully aim more superficially.
Patient returns with skin ulceration at the site.
This is usually a strongly positive test. Prescribe a moderate potency corticosteroid cream.
Risks
Minor bleeding, pain and itching at the site
Anaphylaxis or angioedema due to hypersensitivity to tuberculin
Severe skin reaction with ulceration at the site
Pyrexia
Sharps injury to healthcare personnel
Vasovagal response (fainting)
References
Pahal P, Sharma S. PPD Skin Test. [Updated 2021 Feb 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK556037/
Guidance for National Tuberculosis Programmes on the Management of Tuberculosis in Children. 2nd edition. Geneva: World Health Organization; 2014. Annex 3, Administering, reading and interpreting a tuberculin skin test. Available from: https://www.ncbi.nlm.nih.gov/books/NBK214439/
Joubert A. Administration of injections. In: Mulder M, Joubert A, Olivier N, eds. Practical Guide for General Nursing Sciences. 2nd ed. Pearson; 2020.