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. 2017 Apr 1;56(7):773–779. doi: 10.2169/internalmedicine.56.7533

Table 3A.

Comparison of QFT-GIT and T-SPOT Results for 650 HCWs after Excluding Indeterminate Cases Using Cut-offs of 0.35 IU/mL (QFT-GIT) and Six Spots (T-SPOT) Cut-off with the Exclusion of Borderline Zone.

T-SPOT Total
Positive (≥6 spot) Negative (≤5 spot)
QFT-GIT
Positive (≥0.35 IU/mL) 14 5 19
Negative (<0.35 IU/mL) 13 618 631
Total 27 623 650

The QFT-GIT result was considered positive if the interferon-gamma response in the TB antigen tube after subtracting the response in the Nil tube was ≥0.35 IU/mL, and the T-SPOT result was considered positive if (antigen panel A minus Nil) and/or (antigen panel B minus Nil) ≥6. The QFT-GIT result was considered negative if the interferon-gamma response in the TB antigen tube after subtracting the response in the Nil tube was <0.35 IU/mL, and the T-SPOT result was considered negative if (antigen panel A minus Nil) and/or (antigen panel B minus Nil) was ≤5.