A sputum test for AFB detects acid‑fast bacilli (mainly Mycobacterium tuberculosis) in coughed-up mucus to diagnose and monitor pulmonary tuberculosis. Laboratory methods include smear microscopy (Ziehl–Neelsen or fluorescent stain), culture, and molecular tests (e.g., PCR/GeneXpert). Typically two to three early‑morning deep‑cough samples are collected. A positive result suggests TB; culture or molecular tests confirm species and drug resistance.

Collect early-morning deep-cough sputum (not saliva) after rinsing your mouth with water. Sit upright, take deep breaths, then cough from the chest and expectorate into a sterile, wide‑mouth, leak‑proof container. Provide three specimens (one early morning and two spot or consecutive mornings) if possible. Label and deliver promptly; refrigerate if delay (≤24 hours). Avoid eating or brushing teeth immediately before collection.

Collect three deep‑cough (mucopurulent) sputum specimens for AFB testing, preferably early morning, each about 5 mL. Specimens should be produced on consecutive days or as instructed (sometimes two within 24 hours and one the next day). Avoid saliva; expectorated sputum is required. If unsure about volume or timing, follow the laboratory’s guidance.

Costs vary by country and test type. Simple sputum AFB smear microscopy is often free in public TB programs (including NHS), but private labs typically charge about ₹100–500 (~$2–7) in India and $20–100 in the US. More advanced tests (culture, molecular/NAAT, DST) cost substantially more, commonly $50–300+. Final price depends on lab, location, and processing fees.

An AFB (acid‑fast bacilli) smear indicates presence of acid‑fast organisms but does not definitively confirm tuberculosis. Positive AFB suggests mycobacterial infection but cannot distinguish Mycobacterium tuberculosis from non‑tuberculous mycobacteria. Definitive diagnosis requires culture or molecular tests (NAAT/PCR) and clinical/radiologic correlation; culture also provides drug‑susceptibility information.

AFB culture costs vary widely by country and lab. In India private labs typically charge around ₹500–₹2,500. In the UK the test is usually covered by the NHS; private testing costs roughly £50–£200. In the US expect about $30–$200. Costs depend on method (solid vs liquid culture), location, and any add‑on tests like drug susceptibility, which raise the price.