Quick answer
The TB Gold Test (QuantiFERON) costs ₹4,800 at Live Line Health Care. A blood test that measures how immune cells respond to TB proteins. No fasting is needed. It uses a blood sample and the report is usually ready within 48–72 hours. Book home sample collection or visit any of our 45 centres.
Also known as: QuantiFERON TB Gold, QuantiFERON, TB Quantiferon Gold, IGRA, Interferon Gamma Release Assay, QFT, Latent TB Blood Test
What is the TB Gold Test?
The TB Gold test, widely known as QuantiFERON, is a blood test for tuberculosis infection. It belongs to a group of tests called interferon gamma release assays, or IGRA. Your blood is mixed with proteins found in TB bacteria, and if your immune cells have met TB before, they release a chemical signal called interferon gamma, which the lab then measures. Unlike the Mantoux skin test, it needs a single blood sample and no return visit, and past BCG vaccination does not normally affect it.
The most important thing to know is what this test cannot do. A positive TB Gold shows TB infection at some point in life, but it cannot tell whether the infection is sleeping (latent) or causing active disease, and a negative result does not rule out active TB. It is therefore not the right first test for someone with a long cough. For that, doctors rely on sputum tests such as Sputum AFB and TB PCR, along with a chest X-ray. TB Gold is used mainly before treatments that lower immunity, after contact with TB, and in people at higher risk.
What it measures: Interferon gamma released by immune cells in response to TB proteins, compared against a nil control and a mitogen control.
Parameters included (4)
- QuantiFERON Result: Positive, Negative or Indeterminate
- TB Antigen Response (IU/mL)
- Nil Control
- Mitogen Control
Why is this test done?
- Checking for latent TB before biologics, a transplant, chemotherapy or long-term steroids
- After close contact with a person who has active lung TB
- Screening health workers and others with ongoing exposure
- When BCG may confuse a Mantoux result, or a return visit is difficult
- Assessing latent TB in people living with HIV, on a doctor’s advice
When should you get tested?
- Usually no symptoms, since latent TB does not make you feel ill
- A household member recently diagnosed with TB
- Planned treatment that will weaken the immune system
- A long cough, night sweats or weight loss, which also need sputum tests and a chest X-ray
How to prepare for the TB Gold Test
- 1You can eat and drink as usual before the sample.
- 2Blood goes into special tubes that must be processed within a set time, so please keep to your booked slot.
- 3Tell the staff about steroids, chemotherapy, biologic medicines or HIV, because low immunity can affect the result. Do not stop any medicine unless your doctor asks you to.
- 4Mention any recent Mantoux test or live vaccine.
TB Gold Test normal range
| Parameter | Typical reference range |
|---|---|
| Expected result | Negative: TB response below the cut-off, commonly under 0.35 IU/mL above the nil control |
| Positive | TB response at or above the cut-off, commonly 0.35 IU/mL or more above the nil control |
| Indeterminate | The controls did not behave as expected, so the test cannot be read and may need repeating |
The final reading depends on the test kit’s rules, which also consider the nil and mitogen controls. Your report’s interpretation takes precedence. Ranges are typical adult values and vary between labs, age and sex. Always use the range printed on your report and discuss results with your doctor.
Understanding your results
- A positive result means TB infection is likely at some time in your life. Your doctor will first check for active TB through symptoms, a chest X-ray and sputum tests.
- A negative result makes latent TB less likely, but it can miss very recent infection and does not exclude active TB, particularly with weak immunity.
- An indeterminate result is not a positive. It often reflects low immune response or a sample problem, so a repeat or a different test may be advised.
- The test can stay positive after TB has been successfully treated, so it is not used to check for cure.
TB Gold Test – FAQs
What is the price of the TB Gold Test?
The TB Gold Test (QuantiFERON) costs ₹4,800 at Live Line Health Care, at all 45 centres and for home sample collection.
Does a positive TB Gold test mean I have active TB?
No. It shows that you have been infected with TB at some time, but many such people never fall ill. A doctor must check for active disease with symptoms, a chest X-ray and sputum tests before deciding on anything further.
What is the difference between TB Gold and the Mantoux test?
Both look for TB exposure. Mantoux is a skin injection that must be read after two to three days and can be influenced by BCG. TB Gold is a blood test done in one visit, and BCG does not normally affect it.
I have a long cough. Should I take the TB Gold test?
Usually not as your first test. A cough lasting over 2 weeks needs a doctor’s review, a chest X-ray and sputum testing, which look for active TB directly. A negative TB Gold cannot rule out lung TB, so it may falsely reassure you.
What does an indeterminate QuantiFERON result mean?
It means the lab could not give a clear answer, because the control tubes did not respond as expected. Low immunity, certain medicines or sample handling can cause this. Your doctor may ask for a repeat, or choose another test.
Does a positive TB Gold test always need treatment?
Not always. Once active TB is ruled out, a doctor may advise preventive treatment if you have a higher risk of falling ill, for example with low immunity or recent contact. This decision depends on your health, so follow your doctor’s advice.
Where can I get the TB Gold Test done?
At any of our 45 Live Line Health Care centres in 40 cities across Andhra Pradesh and Telangana, including Hyderabad, Visakhapatnam, Warangal, Kakinada and Nellore, or book home sample collection.
Medical disclaimer: This information is for general awareness only and is not a substitute for professional medical advice. Please consult a qualified doctor to interpret your results and before starting or changing any treatment.