Stillwater Medical | TB Screening (Whole Blood) (2024)

FAQs

How often do you need a CXR for TB screening? ›

If you have a negative skin test, you need a repeat test at least once every four years. If you have a documented positive skin test, you must have an initial chest X-ray. After that, you still need to be screened every four years.

A “positive” TB blood test result means you probably have TB germs in your body. Most people with a positive TB blood test have latent TB infection. To be sure, your doctor will examine you and do a chest x-ray. You may need other tests to see if you have latent TB infection or active TB disease.

Typically, in immunocompetent patients, sufficient peripheral blood mononuclear cells (PBMCs) to perform the T‑SPOT. TB test can be obtained with the following age‑dependent guidelines: Adults and children ≥ 10 years of age: 6 mL. Children ≥2 to <10 years of age: 4 mL.

It usually takes 2 to 10 weeks after exposure to a person with TB disease for the skin test to react positive. The test may also be falsely negative if the person's immune system is not working properly.

The CDC guidelines on the use of QFT recommend that recent contacts who test QFT negative prior to 8 weeks after the end of exposure, be retested 8 to 10 weeks later—similar to the recommendations for the TST. Many other national guidelines recommend a similar approach.

6. How long is the test valid? A negative test is valid for 2 years and must not expire at any time during the semester. If you have submitted a copy of a negative test to us previously and do not know if it has expired, contact us to find out.

In some people, the BCG TB vaccine may cause a positive TB skin test even if they are not infected with TB germs. Unlike the TB skin test, TB blood tests are not affected by prior BCG vaccination. Therefore, TB blood tests are the preferred test for people who have received the BCG TB vaccine.

Active, drug-sensitive TB disease is treated with a standard 6-month course of 4 antimicrobial drugs that are provided with information, supervision and support to the patient by a health worker or trained volunteer. The vast majority of TB cases can be cured when medicines are provided and taken properly.

Although it is spread in a similar way to a cold or the flu, TB is not as contagious. You would usually have to spend prolonged periods in close contact with an infected person to catch the infection yourself. For example, TB infections usually spread between family members who live in the same house.

How accurate is the blood test for TB? ›

Sensitivity of 79% and specificity of 97% with specificity being as low as 59% in BCG-vaccinated patients (high false positive).

No, there is no drug testing.

Tuberculosis (TB) is one of the infectious diseases that may cause death worldwide. Unlike other respiratory infections, TB can lead to permanent lung damage.

Between 20 to 30% of people exposed to a person with active TB become infected. For that reason, doctors usually distinguish between infection (or a positive TB test) and an active infection. After you are infected, your immune system will attack the bacteria.

It usually occurs in the lungs, but it can spread to other parts of the body. TB spreads to other people through the air. When someone with TB breathes out or coughs, the bacteria can be breathed in by people who are nearby. You should not go to work or school while you can infect other people.

The American College of Chest Physicians recommends 8 weeks, the IDSA and the American Thoracic Society say we should repeat imaging only for patients who don't improve in the expected 5-7 days, and the British Thoracic Society suggests 6 weeks for certain high-risk individuals.

The fourth component of a complete TB medical evaluation is a chest x-ray. A patient should have a chest x-ray if he or she has a positive blood test or skin test, or has signs and symptoms of TB disease, or been exposed to someone with TB disease.

In most cases, employees with positive tuberculosis test results will not be able to return to work until they have been cleared by a chest X-ray. That's because the X-ray demonstrates they do not have active tuberculosis.

Chest x-ray should be repeated if HCP or caregiver is symptomatic. Serial follow-up chest x-rays are not recommended, however, an annual TB risk assessment questionnaire and symptom evaluation should be administered. For those determined to have been exposed, perform evaluation for signs and symptoms of TB disease.