A panel of highly sensitive circulating biomarkers for acute liver injury have been identified and demonstrated to identify liver injury on first presentation to hospital before standard tests are elevated in patients with paracetamol overdose. The investigators wish to test these biomarkers in patients with active and latent tuberculosis to see if they can be used to stratify patients undertaking anti-tuberculosis drug therapy. Anti-tuberculosis drug induced liver injury is the most frequent side-effect of anti-tuberculosis therapy, affecting 2-5% of tuberculosis patients seen at the Royal Infirmary Edinburgh and hindering their effective treatment. Patients will be recruited from the TB out-patient clinic at the Royal Infirmary Edinburgh. Blood samples will be taken every time the patient visits the clinic and also retrieved from the biochemistry lab. The biomarkers in the blood samples will be analysed to determine if they rise in patients who develop liver injury.