Flow chart diagram detailing how to read or interpret QFT results

QuantiFERON (QFT) Interpretation

Scenario 1: TB Antigen – Nil ≥ 0.35 IU/mL

  • If yes, move to next step of TB Antigen – Nil ≥ 25% of Nil IU/mL value
  • If yes, move to Nil ≤ 8.0 IU/mL
  • If yes, test is positive

Scenario 2: TB Antigen – Nil ≥ 0.35 IU/mL

  • If no, Mitogen – Nil < 0.50 IU/mL and/or Nil > 8.0 IU/mL
  • If yes, test is indeterminate
  • If no, test is negative

Scenario 3: TB Antigen – Nil ≥ 0.35 IU/mL

  • If yes, move to next step of TB Antigen – Nil ≥ 25% of Nil IU/mL value
  • If no, Mitogen – Nil < 0.50 IU/mL and/or Nil > 8.0 IU/mL
  • If yes, test is indeterminate
  • If no, test is negative

Scenario 4: TB Antigen – Nil ≥ 0.35 IU/mL

  • If yes, move to next step of TB Antigen – Nil ≥ 25% of Nil IU/mL value
  • If yes, move to Nil ≤ 8.0 IU/mL
  • If yes, test is indeterminate
  • If no, test is negative