If you need a TB check, you might hear about two tests. One method involves a skin test, while the other utilizes a blood test. Both look for infection with TB bacteria. They function in different ways. We will clearly explain the difference.
What Are These Tests?
The Mantoux test, also referred to as the TST, is a skin test for TB. A small quantity of liquid is administered just beneath the skin of your arm. You must come back in 2 or 3 days so a nurse can read the spot.
A TB blood test is often called an IGRA. It needs one visit for blood to be drawn. The lab looks for a specific immune response in your blood.
How the TB Skin Test Works
A healthcare worker gives a small dose of tuberculin in the lower arm.
You will have a small raised bump. That is normal.
Return in 48 to 72 hours. A qualified technician will inspect the arm. They look for a raised, complex area. The dimension influences whether the test outcome is positive or negative.
If the skin reacts, it’s a sign your body has met TB bacteria. More tests are needed to confirm active or latent TB.
You can repeat the skin test later. If you do, the second site should be on the other arm.
How the TB Blood Test Works
A nurse takes a small tube of blood. The sample is taken to a lab. The lab checks how your immune cells react to TB proteins.
You usually get only one visit. Results may come back in a few days. The blood test does not require you to return for a reading on your arm.
Blood tests are not the first choice for very young children. It is often used for adults, health-care workers, and people who have had a BCG vaccine.
Who Should Be Tested
Some people should get tested because they face a higher risk. This includes people who:
- Spent time with an individual diagnosed with tuberculosis.
- Came from places where TB is common.
- Live or work in high-risk places like shelters, nursing homes, or jails.
- Work in health care and care for at-risk patients.
People who are at high risk are more prone to getting TB. This group includes:
- People with HIV
- Recently infected individuals
- Young children
- Injection drug users
- Those with weak immune systems
- Older adultsÂ
- People who haven’t had proper TB treatment before.
If your chance of infection is low, testing is usually not needed.
Which Test Is Best For Children?
The skin test is usually preferred for children under five years old. Health workers use skin tests more often for very young kids because they are well-studied and reliable for that age group.
What Do The Results Mean?
Positive skin test or blood test: Your body met TB bacteria. To find out whether you have active TB, you need extra testing, such as a chest X-ray and a check-up by a doctor.
Negative test: Your body did not react. This typically suggests you don’t have tuberculosis. But if you were exposed very recently, the test might not show it yet. Your doctor may repeat the test later.
Both tests help the doctor decide what to do next. No single test can confirm whether you have active TB disease.
Which Test Should I Get?
Your health-care provider will help choose the proper test. They will think about:
- Your age.
- Where you grew up or traveled.
- Your job.
- Recent contact with someone with TB.
- Whether you had the BCG vaccine.
- Test cost and availability.
If you have questions, ask your provider. They can explain which test fits your situation.
About Medicross Clinic and Urgent Care
You can get TB screening at Medicross Clinic and Urgent Care. They provide this along with primary and urgent care services. We provide telemedicine from 8 AM to 5 PM for advice and follow-up. Our team can place and read skin tests, draw blood for TB blood tests, and arrange the follow-up exams you may need. We offer physicals, wound care, and routine tests. If you’re feeling sick or need a TB screen for work, travel, or school, stop by or call us. We’ll help you choose the right test and next steps.
Conclusion
Both tests are valuable tools. The skin test needs two visits. The blood test usually needs one. Which test is better depends on your age, your risks, and your history. If you think a test is necessary for you, talk to a health professional at Medicross Clinic and Urgent Care. They will make testing clear and straightforward.
I can create a short handout for patients or a simple script for staff. Which would be more helpful for you?
FAQs
Q. Do vaccines affect the tests?
A prior BCG vaccine can make the skin test show positive even when you are not infected. The blood test is less likely to be affected by the BCG vaccine.
Q. Do either test hurt?
The skin test makes a small prick. The blood test is similar to a typical blood draw. Both involve only slight, temporary discomfort.