An AFB Drug Susceptibility Panel – 1st Line test is a diagnostic test used to determine how effective the four first-line anti-tuberculosis drugs (Streptomycin, Isoniazid, Rifampicin, and Ethambutol) are against a Mycobacterium tuberculosis (MTB) infection. This is crucial for guiding treatment and managing drug resistance, as the test identifies if the bacteria are susceptible (killed by the drug) or resistant (can grow in the presence of the drug)