Prior to receiving the BCG vaccination, it is essential to undergo a tuberculosis skin/Mantoux test. This test is recommended for individuals aged 7 and above who do not have a history or visible scar from a previous BCG vaccination.
Individuals in healthcare professions or those planning to work or study abroad are also advised to undergo a Mantoux test to confirm their tuberculosis-free status.
Understanding the TB/Mantoux Skin Test
The TB/Mantoux skin test consists of 2 separate appointments:
- Part 1: Tuberculin is injected under the skin on the forearm, forming a small bump. This procedure is typically well-tolerated.
- Part 2: After 48-72 hours, a healthcare provider will examine the skin reaction.
If the test is delayed beyond the recommended timeframe, a new test and injection will be necessary.
It is important to note that the TB/Mantoux skin test is used to determine if a person has been exposed to the bacteria that causes tuberculosis. The presence of a specific reaction on the skin after the injection indicates a possible infection with TB.
It is crucial to follow up with the healthcare provider for the second appointment to ensure accurate results. If there are any concerns or questions about the test, it is recommended to discuss them with the healthcare provider.
Response to BCG Vaccination and Further Evaluation
A mild reaction may occur after BCG vaccination, but it does not necessarily indicate latent TB infection. However, a strong reaction might prompt the need for a chest X-ray.
The course of action following the skin test will be determined based on the individual’s skin response, potentially leading to further treatment or additional tests.
It is important to monitor the site of the BCG vaccination for any signs of infection, such as redness, swelling, or discharge. If any concerning symptoms develop, it is crucial to seek medical attention promptly.
Individuals who have been vaccinated with BCG should inform healthcare providers before undergoing TB testing, as the vaccine can sometimes cause false-positive results. Additional evaluations may be necessary to accurately diagnose TB infection.
Utilizing Interferon Gamma Release Assay (IGRA) for TB Diagnosis
IGRA is a blood test used to diagnose latent TB infection. This test is beneficial in several scenarios, including positive Mantoux test results, previous BCG vaccination, recent relocation to the UK from a TB prevalent region, immunosuppressive treatment, or occupational exposure risks.
Location for Mantoux Skin Testing
If you require a Mantoux skin test, you can visit Olive Health and Travel Clinic at 23A Seven Ways Parade, Woodford Avenue, Ilford IG2 6JX
This informative fact sheet outlines the procedure, outcomes, and implications of the TB skin test. It is crucial for detecting latent TB infection, a key step in preventing active TB disease.
Procedure:
The TB skin test involves injecting a small amount of tuberculin protein under the skin on the forearm. The injection site is then monitored for a reaction, typically within 48-72 hours.
Outcomes:
A positive reaction (induration or swelling) at the injection site may indicate a latent TB infection. Further testing may be needed to confirm the diagnosis.
Implications:
Detecting latent TB infection is important as it can progress to active TB disease if left untreated. Early detection and treatment can help prevent the spread of TB to others.
Preventing Tuberculosis Transmission
Both latent TB infection and active TB disease are treatable with medications. Understanding the phases of tuberculosis is essential as it can be transmitted through the air.
| Stage One – Dormant Tuberculosis Infection | Stage Two – Tuberculosis Becomes Active |
|---|---|
| TB bacteria can lie dormant for years. | Active bacteria can damage tissue. |
| No symptoms visible, regular x-ray. | Symptoms show up, specific tests required. |
| No risk of spreading to others. | Lung bacteria spread through coughing. |
| Treated with a single medication for 9 months. | Multiple medications prescribed for 6 months. |
How can I tell if I have latent TB infection?
The Mantoux TB skin test is used to detect latent tuberculosis. Exposure to active carriers of tuberculosis can lead to the development of latent TB. It is important to examine the test results 2-3 days after the test.
If the test produces a reaction, a bump may appear but will disappear shortly afterward.
It is important to note that having latent TB infection does not mean you have active TB disease. People with latent TB do not feel sick and cannot spread TB to others. However, without treatment, latent TB can progress to active TB disease. It is important to talk to your healthcare provider if you suspect you may have latent TB infection.
How do I take care of my arm after the TB skin test?
- Avoid covering the area with bandages, rubbing, or scratching.
- If the area becomes itchy, use a cold cloth and wash the arm gently.
What if my TB skin test is negative?
A “negative” TB skin test result without a bump indicates the absence of tuberculosis. Further testing may be necessary to confirm the results.
What if my TB skin test is positive?
A “positive” TB skin test indicates the presence of tuberculosis. Additional tests may be required to determine whether the infection is latent or active.
Protect yourself and your family – get tested! Contact your healthcare provider to schedule a TB skin test.
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Abstract
The tuberculin skin test plays a vital role in diagnosing tuberculosis. Interpretation of the results can be complicated due to various factors influencing the outcome of the test. Factors such as prior BCG vaccination, exposure to non-tuberculous mycobacteria, and immunosuppression can all affect the accuracy of the test results.
Keywords: Interpretation, Mantoux test, tuberculosis
INTRODUCTION
In developing countries, TB diagnosis can be challenging due to cost and limitations of testing. The TST remains the primary method for detecting TB infection, despite challenges in interpretation.
The Mantoux test, developed by Koch in 1890 and refined by Mantoux in 1912, is still widely used for tuberculosis diagnosis.
Interpreting the results can be difficult due to factors that affect the accuracy of the test.