Table 4

Reclassification tables to calculate the NRI for binary T-SPOT.TB results in smear-negative children with and without culture-confirmed TB, using the risk categories <10%, 10–30% and >30%*

Clinical+CXR+TST+T-SPOT.TB (expanded model)
Clinical+CXR+TST (baseline model)<10%10–30%>30%Total
Confirmed TB (N=54)
Not confirmed TB (N=437)
  • Numbers in bold indicate correctly-reclassified patients that are used to calculate the NRI.

  • *The risk categories are based on the predicted probabilities from the logistic regression model. The T-SPOT.TB correctly reclassified 3% of culture-confirmed cases (11/54 above the diagonal minus 9/54 below the diagonal). The T-SPOT.TB correctly reclassified 4% of non-confirmed cases (38/437 below the diagonal minus 24/437 above the diagonal). Thus, the overall NRI is 7%.

  • CXR, chest radiography; NRI, net reclassification improvement; PTB, pulmonary tuberculosis; TST, tuberculin skin test.