Quick Answer: How Do You Read QuantiFERON-TB Gold Plus Results?

What is the gold standard for TB diagnosis?

The gold standard for TB diagnosis is either isolation of Mycobacterium tuberculosis (MTB) by culture or detection of MTB-specific nucleic acids by molecular methods [6, 7]..

Will QuantiFERON gold always be positive after treatment?

Since most patients remained QFT-TB positive after therapy, the test should not be used to monitor the effect of preventive therapy. Prospective studies are needed in order to determine the usefulness of IGRA tests during therapy.

Will I always test positive for TB after treatment?

Even after you finish taking all of your TB medicine, your TB skin test or TB blood test will still be positive.

Can QuantiFERON test false positive?

Many institutions have switched from the tuberculin skin test to the Quantiferon (QFT) assay for latent tuberculosis screening. In recent months, we experienced a sharp increase in false-positive QFT results.

What is the normal range of TB?

In a healthy person whose immune system is normal, induration greater than or equal to 15 mm is considered a positive skin test. If blisters are present (vesiculation), the test is also considered positive. In some groups of people, the test is considered positive if induration less than 15 mm is present.

What can cause a false positive TB Gold test?

(1) False-positive results may occur in patients with prior infection with M marinum, M szulgai, or M kansasii. Negative: No IFN-gamma response to M tuberculosis antigens was detected. Infection with M tuberculosis is unlikely.

Is QuantiFERON gold better than PPD?

The QuantiFERON (QFT) blood assay tests for tuberculosis. Patients must get their blood drawn for a QuantiFERON exam. However, QFT candidates receive exam results in 48-72 hours. Compared to PPD wait times, QuantiFERON provides a sizeable advantage.

Is TB Gold test reliable?

QuantiFERON-TB Gold is the most clinically tested and proven IGRA available (2). More than 30 million QFT tests have been sold across 130+ countries, including more than 7 million in 2015. Trust the only blood test for TB infection that offers: The most accurate and reproducible results for TB infection.

What is borderline TB?

A borderline test result (T-Spot only) also indicates an uncertain likelihood of M. tuberculosis infection. A diagnosis of LTBI requires that TB disease be excluded by medical evaluation.

What is the T SPOT test?

The T-SPOT®. TB test is an in vitro diagnostic test for the detection of effector T cells that respond to stimulation by Mycobacterium tuberculosis antigens ESAT-6 and CFP 10 by capturing interferon gamma (IFN- γ) in the vicinity of T cells in human whole blood collected in sodium citrate or sodium or lithium heparin.

How do you read a QuantiFERON-TB test?

The test is considered negative if (mitogen — nil) > 1.5 IU but (tuberculin — nil) < 15% (mitogen -- nil). Results are considered indeterminate if (mitogen -- nil) < 1.5 IU, which might be observed among anergic persons.

What is a positive QuantiFERON-TB Gold test?

If your TST (Mantoux) or Quantiferon blood test was found to be positive, this means you have a latent TB infection, but usually not the active disease.

What happens if I test positive for TB?

If you have a positive reaction to the TB skin test or TB blood test, your doctor or nurse may do other tests to see if you have TB disease. These tests usually include a chest x-ray. They may also include a test of the sputum you cough up.

Can a person with TB go to work?

You need to stay home from work or school so that you don’t spread TB bacteria to other people. After taking your medicine for a few weeks, you will feel better and you may no longer be infectious to others. Your doctor or nurse will tell you when you can return to work or school or visit with friends.

How long does TB Gold results take?

How long does it take to get QFT results? This varies and depends on how frequently the laboratory in your area carries out the test. Results can be available in 24 hours. Unlike the TST, individuals do not need to return 2–3 days later in order to have the test read.

What diagnostic test confirms TB?

The Mantoux tuberculin skin test (TST) or the TB blood test can be used to test for M. tuberculosis infection. Additional tests are required to confirm TB disease. The Mantoux tuberculin skin test is performed by injecting a small amount of fluid called tuberculin into the skin in the lower part of the arm.

What is the best test to detect TB?

The TB skin test, also known as the Mantoux tuberculin skin test, is the most common way doctors diagnose tuberculosis. They’ll inject a tiny amount of fluid called tuberculin just below the skin in your forearm. It contains some inactive TB protein. You should feel a small prick from the needle.