Introduction
The Mantoux test is performed to find out whether a person is infected with tubercle bacilli and to screen latent M. tuberculosis infection. This test is also called the tuberculin test or purified protein derivative (PPD) test.
Definition
The tuberculin skin test is a standardized diagnostic test which is done by injecting PPD intradermally to identify whether an immune response has developed to bacterium that causes TB.
Purposes
- To diagnose latent TB infection.
- To decrease the chance of misinterpretation of a boosted reaction as recent infection.
Indications
- People with HIV infection or another medical problem that weakens the immune system.
- People who;
- Have symptoms of TB.
- Have lived with TB-affected people.
- Live in a country where TB is common.
Contraindications
- Positive TB test in the past.
- Treated with antituberculosis treatment (ATT) in the past.
- Pregnancy.
- People who had MMR (measles, mumps, rubella) vaccines within the past 1 month.
- Those on corticosteroids.
Articles
| Articles | Purpose |
| Purified protein derivative (0.1 mL.) | Antigen used to find the reaction. |
| Tuberculin syringe | To inject the medicine. |
| 26G or 27G needle | To inject intradermally. |
| Alcohol swab | To disinfect the area before injecting. |
| Gloves | To prevent injury and infection. |
Procedure
| Nursing Action | Rationale | |
| 1. | Check whether the patient had any BCG vaccine, recent viral infection, immunosuppression by disease, drugs, or steroids. | Presence of these may cause false readings. |
| 2. | Explain the procedure to the patient. | Wins confidence and allays anxiety. |
| 3. | Wash hands and put on gloves. | Prevents cross- infection. |
| 4. | Draw up 0.1 mL of PPD using tuberculin syringe. | Each 0.1 mL contains 5 tuberculin units. |
| 5. | Cleanse the site (ventral forearm-inner aspect of the forearm, approximately 4 inches below the elbow) with alcohol and let dry. | To prevent infection. |
| 6. | Make a taut on the skin area where the medicine has to be injected. | For easy injection. |
| 7. | Hold the syringe close to the skin with the bevel up, so the hub of the needle touches it as soon as the needle is introduced. | Facilitates injection at the intradermal layer of skin. |
| 8. | Inject the solution, creating a 6- to 10-mm wheel. | Ensures accurate reading. |
| 9. | Remove the needle and place a cotton ball over the injected site. Instruct the patient not to rub/massage the site. | Changes the absorption rate and results. |
| 10. | Discard the needle into the appropriate container as per hospital’s policy. | Prevents needlestick injury. |
| 11. | Reposition the patient. | Enhances comfort. |
| 12. | Mark the site. Record the antigen name, strength, date and time of the test. | Assess whether the induration has increased after 72 hours. |
| 13. | Instruct the patient to come for reading the result after 72 h. | Enhances correct reading. |
| 14. | Document the procedure, including the date, time, and solution used, patient’s response, location of the injection site, and teachings given to the patient. | For further reference and planning of care. |
Interpretation of Test Results
- Read the test site with a millimeter ruler, 48-72 hours after injection. Lightly palpate the site to determine presence or absence of induration.
- Measure the largest diameter of induration and record it in millimeters.
- Also note any erythema at the site. Erythema without induration is not considered significant.
Positive Skin Test
It indicates infection with TB bacteria. Further confirmation has to be done to rule out whether it is latent TB infection or TB disease.
Negative Skin Test
This indicates that the body did not react to the test or induration was not formed.
Interpretation of Induration
- A small reaction (5 mm of firm swelling at the site) is considered to be positive in people who had;
- HIV.
- Undergone organ transplantation.
- Taken steroids/have suppressed immune system.
- Lived in close contact with a person who has active TB.
- Changes on a chest X-ray which indicate TB in the past.
- Larger reactions (greater than or equal to 10 mm) are considered positive in
- People with negative Mantoux test in past 2 years.
- People with chronic illnesses such as diabetes and renal failure.
- Healthcare workers.
- IV drug users.
- Immigrants who have resided in a country where TB prevalence is high.
- Children below 4 years and adolescents who live with infected adults.
- Students and employees of prisons and nursing homes.
- Induration of 15 mm or more is considered positive in any person, even if he/she does not have any risk factors.
False-Positive Reactions
This is a condition in which the person reacts to PPD even when he/she is not infected with M. tuberculosis. Reasons may include the following;
- Infection secondary to other forms of mycobacteria (nontuberculous).
- Prior BCG vaccination.
- Misinterpretation of reaction.
- Inaccurate testing method and antigen.
False-Negative Reactions
In this condition, people do not react to antigen even when they are infected with M. tuberculosis. The reasons may be the following:
- Inability of the skin to react to the injected antigen as a result of weak immune system-cutaneous anergia.
- Very recent (within 8-10 weeks of exposure)/old TB infection (many years).
- Children below 6 months.
- Recent smallpox or measles or any live vaccination.
- Viral illnesses, for example, measles and chicken pox.
- Misinterpretation of reaction.
- Inaccurate testing method and antigen.
Special Considerations
- Avoid testing in patients with active TB, severe skin conditions, or recent viral infections.
- Measure induration only (not redness) in millimeters using a flexible ruler
- Monitor for hypersensitivity reactions (rare).
- Document site, date, time, lot number, and result in mm.
- Educate the patient to avoid scratching and to return for reading.
REFERENCES
- Annamma Jacob, Rekha, Jhadav Sonali Tarachand: Clinical Nursing Procedures: The Art of Nursing Practice, 5th Edition, March 2023, Jaypee Publishers, ISBN-13: 978-9356961845 ISBN-10: 9356961840
- Omayalachi CON, Manual of Nursing Procedures and Practice, Vol 1, 3 Edition 2023, Published by Wolters Kluwer’s, ISBN: 978-9393553294
- Sandra Nettina, Lippincott Manual of Nursing Practice, 11th Edition, January 2019, Published by Wolters Kluwers, ISBN-13:978-9388313285
- Adrianne Dill Linton, Medical-Surgical Nursing, 8th Edition, 2023, Elsevier Publications, ISBN: 978-0323826716
- Donna Ignatavicius, Medical-Surgical Nursing: Concepts for Clinical Judgment and Collaborative Care, 11th Edition ,2024, Elsevier Publications, ISBN: 978-0323878265
- Lewis’s Medical-Surgical Nursing, 12th Edition,2024, Elsevier Publications, ISBN: 978-0323789615
- AACN Essentials of Critical Care Nursing, 5th Ed. Sarah. Delgado, 2023, Published by American Association of Critical-Care Nurses ISBN: 978-1264269884
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