1. Interpretation Criteria for the QuantiFERON-TB Gold Plus Test (QFT-Plus)
View in chapter → Interferon-y Release Assays (IGRAs)
Last Updated April 2026
Possible Test Results
| Nil (IU/ml) | < 8.0 | |
|---|---|---|
| TB1 minus Nil (IU/ml) | > 0.35 and > 25% of Nil | |
| TB2 minus Nil (IU/ml) | Any | |
| Mitogen minus Nil | Any | |
| Report/Interpretation | M. tuberculosis infection likely | |
| Nil (IU/ml) | < 8.0 | ||
|---|---|---|---|
| TB1 minus Nil (IU/ml) | < 0.35 or > 0.35 and < 25 % of Nil | ||
| TB2 minus Nil (IU/ml) | < 0.35 or > 0.35 and < 25% of Nil | ||
| Mitogen minus Nil | > 0.50 | ||
| Report/Interpretation | M. tuberculosis infection not likely |
| Nil (IU/ml) | < 8.0 | > 8.0 |
|---|---|---|
| TB1 minus Nil (IU/ml) | < 0.35 or > 0.35 and < 25% of Nil | Any |
| TB2 minus Nil (IU/ml) | < 0.35 or > 0.35 and < 25% of Nil | Any |
| Mitogen minus Nil | < 0.50 | Any |
| Report/Interpretation | Likelihood of M. tuberculosis infection cannot be determined | |
Source: Based on manufacturer recommendations for QuantiFERON-TB Gold Plus [Package insert].
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