AFB culture (TB culture)
Quick answer: An AFB culture grows mycobacteria, the bacteria that cause tuberculosis (TB), from a sample so they can be identified. It is used to diagnose TB in the lungs or elsewhere in the body, and to test which TB medicines will work.
- SampleSputum, urine, blood or body fluid, depending on where infection is suspected
- TakesAbout 5 to 10 minutes to give a sputum or urine sample
- Before the testFor sputum or urine, an early morning sample is usually requested; follow the lab's instructions for your sample type.
- In fertility careGenital tuberculosis is a known cause of infertility in India, and culture of samples such as menstrual blood or endometrial tissue may be part of its work-up.
How the test is done
- 1You give the sample your doctor asks for, such as early-morning sputum
- 2For sputum, you cough deeply and spit into a sterile container
- 3The lab treats the sample and places it in special growth media
- 4The culture is watched over a long period, as TB bacteria grow slowly
What your results can mean
Reading your report
TB grows slowly, so final results can take several weeks; a negative culture does not always rule out TB, so discuss it with your doctor.
If the result is outside the usual range
Growth of TB bacteria confirms active TB in the part of the body sampled and allows testing of which medicines work. No growth makes TB less likely but does not fully rule it out.
Who usually has this test
People with suspected TB, such as a long cough, fever or weight loss, and some women with suspected genital TB.
Risks and aftercare
There are no risks for sputum or urine samples; other samples carry the risks of the procedure used.
Names and options
Also called: TB culture, mycobacterial culture, BACTEC culture, MGIT culture, AFB culture
Options
- Blood
- Body fluid
- Urine
- Sputum
- BACTEC (automated) culture
Listed by the hospital as
- AFB CULTURE, BLOOD (AUTOMATIC)
- AFB CULTURE, FLUID (AUTOMATIC)
- AFB CULTURE, URINE (AUTOMATIC)
- BACTEC_AFB CULTURE
- SPUTUM AFB CULTURE
Questions about this test
Why does a TB culture take longer than other cultures?
TB bacteria grow much more slowly than most bacteria, so cultures are watched over many weeks. Ask the hospital when to expect your result.
How do I give a good sputum sample for TB?
Give it early in the morning before eating, after rinsing your mouth with water. Cough deeply from the chest and spit phlegm, not saliva, into the container.
Can genital TB be found with this test?
Yes, a culture of menstrual blood or womb lining tissue can sometimes find genital TB, which can affect fertility. It can be missed, so doctors also use other tests.
Related tests
Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
Get directions ↗IVF Pulse fertility care at Tamara Hospital →
Reception
Waiting area
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This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.