Tuberculosis Testing: Your Questions Answered

Q: Tuberculosis Testing: Your Questions Answered

DEAR Ruru： I apologize for the late reply. <br>Regarding your questions： <br>1. <br>The diagnosis of pulmonary tuberculosis requires three criteria： 1) clinical symptoms, 2) chest X-ray (CXR), and 3) microbiological evidence. <br>At least two of these must be met for a diagnosis,

Tuberculosis Examination

I would like to ask the doctor a few questions:
1.
Since mid-July, I caught a cold from a classmate, which led to fever and phlegm in my throat (I usually have phlegm in my throat as well, but a traditional Chinese medicine practitioner said it was due to my stomach issues causing a foreign body sensation in my throat).
Because of the phlegm, I have been coughing (sometimes it feels like there is air in my lungs that I want to cough out).
Later, I received a call from the health center stating that a classmate might have tuberculosis, and we were advised to undergo a skin test.
I went for the skin test on August 1, but my cold has not yet resolved, so I still have phlegm in my throat and continue to cough, mainly trying to expel the phlegm.
I noticed that tuberculosis symptoms seem similar, which made me quite anxious.
However, the result on Friday was only 5mm, so I would like to ask if I might be suspected of having tuberculosis?
2.
When will the area where the skin test was administered start to decrease in size?
3.
If I want to go for further examination at the hospital, will it still be the skin test? I have sensitive skin, and even a little dust (like dog hair) makes my skin itchy, so I would like to know if there are alternative testing methods?
4.
Which hospital in Changhua can perform the test? Is it Changhua Christian Hospital?

Ru Ru, 20~29 year old female. Ask Date: 2012/08/08

Dr. Huang Yiwen reply Pulmonology

DEAR Ruru: I apologize for the late reply.
Regarding your questions:
1.
The diagnosis of pulmonary tuberculosis requires three criteria: 1) clinical symptoms, 2) chest X-ray (CXR), and 3) microbiological evidence.
At least two of these must be met for a diagnosis, so it appears that you do not currently have these factors.

2.
The timeframe is about 1-2 weeks, but it varies from person to person; however, that is not a concern.

3.
No, just a chest X-ray is sufficient.

4.
Both Changhua Christian Hospital and Changhua County Health Bureau are acceptable options.

5.
There is an antibody test available, but since your tuberculin test (TT) is only 5 mm, it is not necessary to perform it.

GOOD DAYS,
Huang Yi-Wen

Reply Date: 2012/08/08

More Info

Understanding tuberculosis (TB) testing can be quite complex, especially when considering the various symptoms and testing methods involved. Let's address your questions one by one.

1. Regarding your symptoms and the skin test result: It’s understandable to feel anxious given your recent health issues and the potential exposure to TB. The skin test (also known as the tuberculin skin test or Mantoux test) measures your immune response to a protein derived from the TB bacteria. A result of 5mm is generally considered negative, especially in individuals without risk factors for TB. The typical thresholds for interpreting the test are as follows:
- 5mm or more is positive for individuals with certain risk factors (like HIV infection or recent TB exposure).

- 10mm or more is positive for individuals with moderate risk factors (like recent travel to endemic areas).

- 15mm or more is positive for those with no known risk factors.

Given your result of 5mm and the absence of significant symptoms typical of active TB (like persistent cough, weight loss, night sweats, or hemoptysis), it is unlikely that you have active TB. However, if you continue to have symptoms or if you have further concerns, it would be wise to consult a healthcare provider for a thorough evaluation.

2. Regarding the skin test site: The reaction at the test site typically resolves within 1-2 weeks, although this can vary from person to person. If you notice prolonged redness or swelling, it’s advisable to consult a healthcare professional.

3. Alternative testing methods: If you have sensitive skin and are concerned about the skin test, there are alternative methods for TB testing. One such method is the Interferon Gamma Release Assays (IGRAs), which are blood tests that measure your immune response to specific TB proteins. These tests are not affected by prior BCG vaccination and have a higher specificity than the skin test, making them a good option for individuals with sensitive skin or those who have had a history of false positives with the skin test.

4. Where to get tested in Changhua: In Changhua, you can get TB testing done at various hospitals, including Changhua Christian Hospital (彰化基督教醫院) and Changhua County Hospital (彰化縣醫院). It’s best to call ahead to confirm that they offer the specific tests you’re interested in, such as the skin test or IGRA.

In summary, while your symptoms and the recent exposure to TB may understandably cause concern, the skin test result of 5mm is not indicative of TB infection, especially in the absence of significant symptoms. If you continue to feel unwell or have concerns about your health, it’s important to follow up with a healthcare provider who can offer further testing or evaluation. Additionally, exploring alternative testing methods like IGRA may provide you with peace of mind given your sensitive skin. Always prioritize open communication with your healthcare provider to ensure you receive the best care tailored to your needs.

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