Understanding Your Laboratory Test: A Patient Guide
This test identifies and grows bacteria from a sputum sample to determine what germ is causing a respiratory infection.
{"A sputum culture helps identify the specific bacteria causing your lung infection","The test guides doctors in choosing the most effective antibiotic treatment","Results typically take 2-3 days as bacteria need time to grow"}
Key facts at a glance
- LOINC
- 17897-0
- Short code
- SPBACT6
- Synonyms
- Bacteria Spt Aerobe Cult org #6
- Category
- chemistry
- Sample
- sputum
- Container
- Sterile, wide-mouth, leak-proof sputum collection container
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- aerobic-culture
- CPT
- 87070
- SNOMED
- 119376003
- Specimen volume
- 1-2 mL of sputum (not saliva); minimum 1 mL acceptable
- Stability
- Room temperature: 2 hours; Refrigerated (2-8°C): 24 hours; Do not freeze
- TAT
- 48–72 hours
- Order
- routine
This laboratory test measures specific substances in your body to help your healthcare provider evaluate your overall health, screen for certain conditions, or monitor a treatment plan you may already be following. Your results are always interpreted together with your symptoms, medical history, and physical examination to give a complete picture of your health.
A sputum bacterial culture is a laboratory test that collects and grows bacteria from your sputum (mucus from your lungs) to identify what germ is causing your respiratory infection. The '#6' in the test name refers to the specific type of bacteria being looked for in this particular test panel.
The sample is usually collected at a clinic, hospital, or laboratory draw station. A trained phlebotomist will clean the site, typically the inside of your elbow, draw a small amount of blood into a sterile tube, and apply a bandage. Some tests may instead require a urine, saliva, or swab sample, and your provider will give you specific instructions beforehand, including whether fasting is needed.
You will be asked to cough deeply from your lungs and spit mucus into a sterile container. It is important to avoid saliva or nasal secretions, as the sample should come from your lower airways. Your healthcare provider will give you specific instructions on how to collect a proper sample.
Once your sample arrives at the laboratory, trained technologists label, process, and analyze it using specialized instruments and validated testing methods. Results are carefully reviewed for accuracy and quality control before being reported to your healthcare provider, who will contact you to discuss the findings and explain what they mean for your ongoing care.
The sputum sample is placed on special growth materials and kept at body temperature. If bacteria are present, they will multiply and form colonies over 2-3 days. Lab technicians then identify the specific bacteria and test which antibiotics can effectively treat the infection.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Rinse mouth with water prior to collection. Avoid eating, drinking, or using mouthwash for at least 1 hour before specimen collection. Prior antibiotic therapy should be noted on the requisition.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Sputum culture results help your doctor determine the exact cause of your respiratory symptoms such as persistent cough, fever, or difficulty breathing. This information is crucial for prescribing the most appropriate antibiotic, ensuring effective treatment and helping combat antibiotic resistance.
Frequently asked questions
Does this test hurt?
How long does it take to get results?
Do I need to prepare for this test?
What if no bacteria grow in the culture?
Sources
- 1
- 2
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy