✍️ Edited by Farhan Ahmed, Editor, MedTestBD · Last updated: August 2026
What is a Blood Culture & Sensitivity Test?
A Blood Culture and Sensitivity (C/S) test detects bacteria or fungi circulating in the bloodstream — a serious condition called bacteraemia or septicaemia. A blood sample is placed in a culture medium and incubated to see if any microorganisms grow. If they do, a sensitivity test then identifies which antibiotics can effectively kill them. It is the definitive test for diagnosing bloodstream infections and guiding antibiotic treatment.
Why is the Blood C/S Test Done?
- To diagnose sepsis — a life-threatening infection of the bloodstream causing fever, rapid heart rate, and low blood pressure
- To identify the causative organism in unexplained high fever lasting more than 3–5 days
- To diagnose typhoid fever — Salmonella typhi grows in blood culture, especially in the first week of illness
- To guide antibiotic selection — the sensitivity report shows exactly which antibiotics the identified bacteria responds to
- To detect infective endocarditis — bacterial infection of the heart valves
- To investigate fever in immunocompromised patients, such as those on chemotherapy
Understanding the Results
| Result | Interpretation |
|---|---|
| No growth after 5–7 days | No significant bacteria detected — infection less likely or already treated |
| Growth detected | Organism identified — sensitivity report guides antibiotic choice |
| Sensitive (S) | The antibiotic is effective against the identified organism |
| Resistant (R) | The antibiotic will not work — choose another |
| Intermediate (I) | Borderline — higher dose may be effective |
Results typically take 3–7 days as the bacteria need time to grow. In urgent situations, doctors begin empirical antibiotics while waiting and adjust once the culture result is available.
How to Prepare for the Blood C/S Test
- No fasting is required
- Ideally, the sample should be collected before starting antibiotics — antibiotics suppress bacterial growth and can cause a false negative result
- Blood is best collected during a fever spike, when bacteria are most likely to be in the bloodstream
- Inform the doctor about any antibiotics you have already taken
- Two or more samples from different sites are often collected to improve accuracy and rule out contamination
Blood C/S Test Price in Bangladesh
Blood culture and sensitivity test prices vary between diagnostic centers across Bangladesh. Compare blood C/S test prices on MedTestBD →
Normal ranges cited on this page are based on MedlinePlus and WHO guidance. Prices are collected from public sources and may change — confirm with the facility before visiting. This information is for general reference only and is not medical advice. Always consult a qualified physician.
