This method cannot be applied if Mantoux test (tuberculin skin test) has been done within the last 40 days, because it can hamper the results of the ALS test. This test is used as a complementary test to other tests, e.g. chest X-ray, ESR, CRP, history of contact with active TB case, failure with conventional antibiotic treatment etc.; anti-TB therapy is not provided if only ALS test is positive. The reason is that this method is potentially an early biomarker of active infection. However, if a subject does not show any physical symptoms, the doctors cannot prescribe anti-TB treatment.