âī¸ Written by the MedTestBD Editorial Team ¡ Last reviewed: June 2026
What is a Sputum Culture & Sensitivity Test?
A Sputum for Culture and Sensitivity (C/S) test grows bacteria from a sputum sample in a laboratory to identify the exact organism causing a respiratory infection. Once the organism is identified, a sensitivity panel tests which antibiotics can effectively kill it. Unlike the AFB smear which gives rapid visual identification, culture provides definitive species identification and a precise antibiotic guide â essential for treating difficult or recurrent chest infections.
Why is the Sputum C/S Test Done?
- To identify the specific bacteria causing pneumonia, bronchitis, or lung abscess
- To guide antibiotic selection in patients who are not responding to initial treatment
- To detect antibiotic-resistant organisms such as MRSA or multi-drug resistant (MDR) bacteria
- To diagnose TB mycobacterial infections when AFB smear is negative but clinical suspicion remains â culture is more sensitive than smear
- To investigate recurrent chest infections in patients with COPD, bronchiectasis, or cystic fibrosis
- To confirm the causative organism in hospitalised patients with severe respiratory infections
Understanding Sputum C/S Results
| Result | Interpretation |
|---|---|
| No growth after 48â72 hours | No significant bacterial pathogen detected â viral infection or inadequate sample possible |
| Growth identified | Organism named â sensitivity panel guides antibiotic choice |
| Sensitive (S) | Antibiotic is effective â can be used for treatment |
| Resistant (R) | Antibiotic will not work â choose an alternative |
| TB culture positive | Takes 2â8 weeks â confirms TB even when smear was negative |
Standard bacterial culture results are available in 48â72 hours. TB culture takes much longer â 2 to 8 weeks â because mycobacteria grow slowly. Rapid molecular tests such as GeneXpert MTB/RIF provide TB results within hours and are increasingly available in Bangladesh.
How to Prepare for the Sputum C/S Test
- Collect an early morning sample â overnight secretions accumulate in the airways and give the highest bacterial yield
- Rinse your mouth with water before collecting â do not use mouthwash or toothpaste, as antibacterial agents reduce bacterial yield
- Take a deep breath and cough forcefully from deep in the chest â the sample must be sputum from the lungs, not saliva
- Collect before starting antibiotics if at all possible â antibiotics rapidly suppress bacterial growth
- Use the sterile container provided by the lab and deliver within 1â2 hours, or refrigerate if delayed
Sputum C/S Test Price in Bangladesh
Sputum culture and sensitivity test prices vary between diagnostic centers across Bangladesh. Compare sputum C/S test prices on MedTestBD â
â ī¸ This information is for general reference only. Always consult a qualified physician before undergoing any medical test.