How do you interpret QuantiFERON TB Gold results?

The QuantiFERON(R) TB Gold (in Tube) assay is intended for use as an aid in diagnosis of TB infection. Negative results suggest that there is not TB infection. In patients with high suspicion of exposure, a negative test should be repeated. A positive test indicates infection with Mycobacterium tuberculosis.

What does QuantiFERON gold positive mean?

A positive response to the QuantiFERON Tb Gold Test indicates towards the infection with the Mycobacterium tuberculosis. Although it does not mean that the person has active TB, rather it simply means that the person has been exposed to the mycobacterium tuberculosis bacterium.

What is a normal QuantiFERON TB Gold?

The QuantiFERONR TB Gold Plus (in Tube) assay is intended for use as an aid in diagnosis of TB infection….

Components	Reference Interval
QuantiFERON-TB Gold In-Tube	Negative
QuantiFERON-TB1 minus NIL	0.34 IU/mL or less
QuantiFERON-TB2 minus NIL	0.34 IU/mL or less
QuantiFERON MITOGEN minus NIL	No reference interval

What does QuantiFERON Gold measure?

QuantiFERON-TB Gold (QFT®) is a whole-blood test that measures the cell-mediated immune response of tuberculosis (TB) infected individuals.

What is nil and Mitogen?

• Mitogen-Nil The maximum non-specific stimulated interferon- gamma level that may be produced by the patient’s lymphocytes minus the Nil (i.e., basal) level of interferon-gamma. (The reporting range for the Nil is 0 – >8.0. The reporting range for the Tb Antigen-Nil and Mitogen-Nil is 0 – >10 IU/mL.)

How do you read IGRA results?

A positive test result suggests that M. tuberculosis infection is likely; a negative result suggests that infection is unlikely. An indeterminate result indicates an uncertain likelihood of M. tuberculosis infection.

How do you know a TB test is positive?

How do I know if I have TB infection? A skin test is the only way to tell if you have TB infection. The test is “positive” if a bump about the size of a pencil eraser or bigger appears on your arm. This bump means you probably have TB infection.

What is nil tube value?

The NIL tube value indicates if the patient has an ongoing immune response which can cause a false-positive result. The NIL tube must be ≤ 8.0 IU/mL. Significance of the MITOGEN result: The mitogen control tube addresses the immune competence of the patient’s immune cells to produce interferon-γ.

What is the normal range for tuberculosis?

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.

Is QuantiFERON gold always positive?

After three months 87.5% were still QFT-TB positive (35/40 tested) whereas after 15 months, one year after the end of therapy, 84.6% remained positive (22/26 tested). All patients with reversed QFT-TB test after three months were still negative at 15 months.

What is normal TB Mitogen?

(The reporting range for the Nil is 0 – >8.0. The reporting range for the Tb Antigen-Nil and Mitogen-Nil is 0 – >10 IU/mL.)

What is Mitogen in QuantiFERON?

The purpose of the mitogen tube in the QFT assay is to serve as a positive control, providing both information about correct blood sample handling and potential information about the immune status of the patient. The mitogen control is independent and not considered in the determination of a positive result.

What does positive IGRA mean?

A positive IGRA test means that you have been infected with tuberculosis. This does not mean that you are ill. It is believed that approximately 1/3 of the world’s population are IGRA positive without suffering from tuberculosis, meaning they have what is called latent tuberculosis infection.

What is a positive TB test look like?

A positive TB skin test will look like a firm, red bump. Your provider will measure the size of the firmness of the bump (induration). Your provider considers your particular risk factors to determine the results of your test.

Will QuantiFERON gold always be positive after treatment?

What can causes a positive QuantiFERON gold?

While ESAT-6 and CFP-10 are absent from all bacille Calmett-Guerin (BCG) strains and from most known nontuberculous mycobacteria, it is possible that a positive QFT-Plus result may be due to infection with M kansasii, M szulgai, or M marinum. If such infections are suspected, alternative tests should be performed.

What can cause a positive QuantiFERON?

The elevated proportion of positive QFTs returned to baseline after switching to a new lot of tuberculosis antigen tubes. Direct comparison of the tubes with tubes from a different lot identified that a lot-specific problem with the tuberculosis antigen tubes was the root cause of false-positive results.

How to read Quantiferon Gold?

QuantiFERON-TB Gold (QFT) is a simple blood test. It helps to detect Mycobacterium tuberculosis, the bacteria which causes tuberculosis (TB). QFT uses unique blood collection tubes that enable immediate exposure of viable blood lymphocytes to highly specific TB antigens (ESAT-6/CFP-10/TB-7.7 (p4)). Antigen exposure produces a quantifiable

Will Quantiferon Gold always be positive?

The TST will eventually become an inaccurate measurement of a TB infection because of what is known as the “booster” effect. After several skin tests, it is common for false positives to be read. The QuantiFERON-TB Gold blood test eliminates this effect completely. It is accurate.

What does a positive Quantiferon Gold test mean?

The QuantiFERON -TB Gold test (QFT …. A positive result suggests that M. tuberculosis infection is likely; a negative result suggests that infection is unlikely; and indeterminate result suggests QFT-G results cannot be interpreted as a result of low mitogen response or high background response.

How to interpret QuantiFERON results?

QuantiFERON-TB Gold Plus: Results and Interpretation When it comes to result calculation, qualitative cutoff values, and result interpretation, the QFT-Plus is identical to the QFT-Gold assay, with the key exception that if either one or both of the QFT-Plus TB antigen tubes are equal to or greater than 0.35 IU/mL and are at least 25% of the