From the Guidelines
For a patient with a negative QuantiFERON-TB Gold Plus test result, no further action regarding tuberculosis treatment is typically needed if there are no other risk factors or clinical concerns. The negative result indicates that the patient likely does not have latent tuberculosis infection (LTBI) [ 1 ]. However, clinical context remains important. If the patient is severely immunocompromised, a single negative test may not definitively rule out LTBI due to potential false negatives in these populations. Some key considerations include:
- The patient's immune status: Those who are immunocompromised because of HIV infection, or those who will undergo treatment with TNF-a antagonists, might need treatment or closer monitoring for disease [ 1 ].
- Recent TB exposure: If the patient has had a recent TB exposure (within 8-10 weeks), the test might be falsely negative since it takes time for the immune response to develop.
- Clinical judgment: Should guide whether additional testing like a tuberculin skin test might be warranted for severely immunocompromised patients.
- Local guidelines: Routine TB screening intervals should follow local guidelines based on the patient's ongoing risk factors. In general, for most immunocompetent patients, the negative QuantiFERON result is reliable and reassuring [ 1 ].
From the Research
Next Steps for a Patient with a Negative QuantiFERON-TB Gold Plus Test Result
- A negative QuantiFERON-TB Gold Plus test result indicates that the patient is unlikely to have latent tuberculosis (TB) infection 2.
- According to the study by 2, a borderline range (0.20 to 0.99 IU/ml) around the cutoff (0.35 IU/ml) has been suggested for the earlier QFT version, but the clinical utility of this range for QFT-Plus is still being evaluated.
- The patient's test results show QuantiFERON TB1 Ag Value of 0.11 IU/mL and QuantiFERON TB2 Ag Value of 0.10 IU/mL, which are both below the cutoff value, indicating a negative result.
- As the patient has a negative result, treatment of latent TB infection is not recommended, unless an individual has been recently infected 3.
- The study by 4 suggests that a negative QuantiFERON-TB Gold In-Tube result is a useful screen tool for latent TB infection, and patients with negative results can be considered for initiation of anti-TNF treatment without further evaluation for TB.
Clinical Implications
- The negative QuantiFERON-TB Gold Plus test result can be used to rule out latent TB infection in patients, especially those who are about to start treatment with infliximab or other anti-TNF agents 4.
- However, it is essential to note that a negative result does not completely exclude the possibility of TB infection, especially in patients with immunocompromised conditions or those who have been recently exposed to TB 5.
- Further evaluation and testing may be necessary for patients with symptoms or risk factors for TB, regardless of their QuantiFERON-TB Gold Plus test result 5.