The objective is to achieve 90% overall, positive and negative clinical concordance between results of the T-SPOT.TB assay, using cells isolated via density gradient centrifugation and positive selection using the T-Cell Select kit, between 0-55 hours following venepuncture

In this study, clinical concordance between results of the T-SPOT.TB assay, using cells stored for 0-8 hours post venepuncture and isolated via density gradient separation and positive selection with magnetic bead isolation using the T-Cell SelectTM Kit will be assessed. Concordance between results of the T-SPOT.TB assay at 0-8 hours post venepuncture and using cells isolated with density gradient centrifugation and results obtained from cells isolated using the T-Cell Select Kit, following storage between 0-55 hours post venepuncture, will be assessed.

Subjects presenting at sites enrolling "suspected of having TB infection" population Inclusion Criteria

• Be able to provide informed consent
• Be able to provide a minimum of 7 mL and maximum of 20 mL of whole blood.
• Have suspected TB infection.
• Be at least 18 years of age.
• Live in a high endemic area for TB infection

Exclusion Criteria

• Unable to meet inclusion criteria

Subjects presenting at sites enrolling "no (or minimal) TB risk factors" population Inclusion Criteria

• Be able to provide informed consent
• Be able to provide a minimum of 7 mL and maximum of 20 mL of whole blood.
• Have no suspicion TB infection.
• Be at least 18 years of age.
• Live in low endemic area for TB infection
• Have no previous medical record of TB infection

Exclusion Criteria

• Unable to meet inclusion criteria
• Current/previous TB diagnosis

Subjects presenting at sites enrolling "low/intermediate TB risk factors" population Inclusion Criteria

• Be able to provide a minimum of 7 mL and maximum of 20 mL of whole blood.
• Have no suspicion TB infection.
• Be at least 18 years of age.
• Live in an low/intermediate endemic area for TB infection Exclusion Criteria
• Unable to meet inclusion criteria

This evaluation will collect blood samples from subjects suspected of having TB infection and, samples from a low risk control population with no (or minimal) TB risk factors. All subjects presenting at participating clinics will be eligible for enrolment into the study provided they meet the inclusion/exclusion criteria outlined in section 4. Based on previous experience and the medical profile of the patient attending each of clinics at the four study sites, it is expected that the sites will individually, and collectively, yield a range of positive and negative assay results required to assess the impact of the T-Cell Select kit on positive and negative agreements of the T-SPOT.TB test.