An AFB (Acid-Fast Bacilli) Drug Susceptibility Panel for a “2nd test” likely refers to testing for resistance to second-line anti-tuberculosis drugs after a first-line drug susceptibility test has been performed or suspected to have failed. This test, often using the MGIT method on a pure culture of Mycobacterium tuberculosis, checks the bacteria’s response to key second-line drugs like Kanamycin, Ethionamide, PAS, and Ofloxacin (the “KEPO” panel) to guide treatment for drug-resistant tuberculosis (TB)