What is a TB PPD Skin Test

The TB skin test is a traditional and widely used screening method. A small amount of purified protein derivative (tuberculin) is injected under the skin on the forearm

How it Works

• Donor receives donor pass and proceeds for initial tuberculin injection
• This test requires the donor to follow-up visit within 48–72 hours to have the results read
• A trained healthcare professional examines the site for a reaction, which indicates potential TB infection

What is a TB Skin Test Used For?

• Routine screenings for schools, workplaces, and healthcare settings
• Those requiring a low-cost, reliable initial screening method

What is a QuantiFERON Gold TB Test

The QuantiFERON Gold TB blood test s a modern blood test offering fast, accurate results without the need for multiple appointments. The QuantiFERON Tb Test is (often abbreviated as QFT or QFT-Plus in its latest version)

Key Advantages:

• Performed in one visit- no return appointment required
• Not affected by prior BCG vaccination, which can cause false positives in skin tests.
• No risk of subjective reading differences or human error

What is a QuantiFERON TB Test Used For?

• Screening for TB infection in workplaces (e.g., healthcare, schools, government).
• Pre-employment testing
• Immigration, travel, or school requirements.
• When accuracy is especially important (e.g., individuals vaccinated with BCG).

What is an T-SPOT®.TB Test

The T-SPOT®.TB test is an advanced, laboratory-based blood test that detects the presence of T cells responding to Mycobacterium tuberculosis antigens. This method captures interferon gamma (IFN-γ) released by immune cells when exposed to TB proteins, providing a highly sensitive and specific result. FDA-approved and widely used for detecting latent TB infection and supporting active TB evaluation.

Key Benefits

• Aids in the diagnosis of latent and active TB infection
• Useful when skin test results are unclear or affected by prior BCG vaccination
• Performed in a single visit with results reviewed by certified labs
  
  

What is a T SPOT TB Test Used For?

• Employment & Occupational Screening: Healthcare workers, teachers, government employees, and others in safety-sensitive positions often need TB clearance.
• Immigration / Visa Requirements: Many countries accept the T-SPOT.TB as proof of TB screening.
• School & University Enrollment: Students (especially in medical or childcare fields) may be required to take it.
• Medical Evaluation: Doctors may order it for patients with risk factors, immune system concerns, or a history of TB exposure.
• When BCG Vaccine Has Been Given: Unlike the TB skin test, the T-SPOT.TB is not affected by prior BCG vaccination, which helps avoid false positives.

What is Tuberculosis?

Tuberculosis (TB) is an infectious disease caused by bacteria that spread through the air from person to person. While TB most commonly affects the lungs, it can also impact other areas of the body, including the brain, kidneys, and spine. Without proper treatment, TB can become life-threatening.

There are two main states: latent TB infection (you have TB bacteria in your body but no symptoms, non-infectious) and active TB disease (you have symptoms, can spread it)

Testing helps identify who has been exposed or infected, even if they are not yet sick, so they can get treatment if needed and prevent spread.

What happens if the test is positive or negative?

• Positive results for a skin or blood test means you have likely been infected with the TB bacteria. This does not tell you if it is an active infection. To check for active TB, doctors will often order a TB chest x-ray and sputum test 
• Negative results means that no evidence (by that test result) of infection. Sometimes this isn't perfect, for example, a very recent infection might not yet be detected, or immune suppression might reduce response.

What are the side effects of risks of TB tests?

• Very minimal
• Skin test-mild pain, redness, swelling at the injection site
• Blood test- pain or bruising at needle site. Rare allergic reaction possible

How often should I be tested for TB?

This will depend on a person's risk factor. People who work in healthcare, live in high TB burden settings or have certain medical conditions might need regular testing. For most people, they only need to be tested when there is an immediate risk or exposure.