A positive gold test, specifically referring to the QuantiFERON-TB Gold+ (QFT-Plus) test, indicates that a person is likely infected with the bacteria that cause tuberculosis (TB).
Understanding the QuantiFERON-TB Gold+ Test
The QuantiFERON-TB Gold+ (QFT-Plus) is a modern diagnostic tool used for the diagnosis of infection with Mycobacterium tuberculosis complex organisms, which include M. tuberculosis, M. bovis, and M. africanum. As referenced, this blood test serves as an alternative to the traditional tuberculin skin testing (TST) for identifying latent tuberculosis (TB) infection.
Unlike the skin test, which involves injecting a substance under the skin and measuring a reaction, the QFT-Plus is a blood draw. The test works by measuring a person's immune response to specific proteins from the TB bacteria.
What Does a Positive Result Mean?
A positive QuantiFERON-TB Gold+ test result means that the individual's blood reacted to the TB proteins in the test. This reaction suggests that the person has been infected with TB bacteria at some point.
Key Implications of a Positive QFT-Plus Test:
- Infection Present: The result indicates that Mycobacterium tuberculosis bacteria are likely present in the person's body.
- Latent or Active TB: A positive test alone cannot distinguish between latent TB infection and active TB disease. Further evaluation, such as chest X-rays, symptom assessment, and potentially sputum tests, is required to determine if the person has active TB disease or latent TB infection.
- Need for Further Evaluation: A healthcare provider will typically order additional tests and evaluations following a positive QFT-Plus result to make a definitive diagnosis and determine the appropriate course of action.
Summary Table: QFT-Plus Positive Result
| Test Name | Sample Type | What a Positive Result Indicates | Used For |
|---|---|---|---|
| QuantiFERON-TB Gold+ (QFT-Plus) | Blood | Likely infection with Mycobacterium tuberculosis complex organisms | Diagnosis of latent or active TB infection |
A positive QuantiFERON-TB Gold+ test is an important piece of information in diagnosing TB infection. It signals the need for further medical assessment to understand the status of the infection and plan necessary treatment or preventive therapy.
