Blood Culture Test: Detecting Bacteria in Your Blood to Diagnose Bacteremia and Sepsis
A laboratory test that detects and identifies bacteria in your blood to help diagnose infections.
{"The test involves growing bacteria from a blood sample in a laboratory","It helps doctors identify the specific type of bacteria causing infection","Results guide appropriate antibiotic selection","Results typically take 2-5 days","A positive result confirms bacterial infection"}
Key facts at a glance
- LOINC
- 44845-6
- Short code
- BCTID5
- Synonyms
- Bacteria Spec Cult org #5
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, leak-proof container appropriate for specimen type; transport media if delayed processing anticipated; specific containers vary by specimen source (e.g., blood culture bottles, sterile cups, swab transport systems)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–999 years
- Method
- culture
- CPT
- 87077
- SNOMED
- 119376003
- Specimen volume
- Variable by specimen type; minimum volume as required by laboratory protocol (typically 0.5-10 mL depending on source)
- Stability
- Process immediately or transport to laboratory promptly; refrigerated (2-8°C) for most specimens if delay >2 hours; room temperature acceptable for some specimens (e.g., urine for culture); refer to specific specimen type guidelines
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
What is this test and why might my doctor order it to check my blood?
A bacterial culture test is a laboratory procedure where a sample of your blood is placed in a special environment that allows bacteria to grow. This helps doctors identify whether bacteria are present in your bloodstream and determine exactly what type of bacteria is causing an infection. The term 'Bacteria # 5' refers to the laboratory process of identifying specific bacterial organisms found in the specimen through culture methods.
How is the test performed, and what should I expect during the blood draw?
A healthcare provider will draw a blood sample from a vein in your arm. The sample is then sent to a laboratory where it is placed in culture bottles containing nutrients that support bacterial growth. These bottles are incubated at body temperature and monitored daily for signs of bacterial growth. If bacteria grow, further tests are conducted to identify the specific type.
What do the results of this test mean for my health and treatment?
A positive result means bacteria were found in your blood, indicating a bacterial infection such as bacteremia or sepsis. Identifying the specific type of bacteria helps your doctor choose the most effective antibiotic treatment for your condition. A negative result means no bacteria were detected in the sample, but this does not completely rule out an infection, since the number of bacteria may be too small to detect or the infection may be located in a different part of the body.
Reference range
No growth of pathogenic bacteria (result reported as organism identified with colony count and antimicrobial susceptibility when clinically indicated)N/A
Specimen collection should be performed prior to initiation of antimicrobial therapy when possible. For specific specimen types, follow site-specific collection guidelines to minimize contamination. Patient should be informed about proper collection technique based on specimen source.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is crucial for diagnosing bloodstream infections, sepsis, and bacterial endocarditis. It helps differentiate between bacterial and viral infections, ensuring appropriate treatment. The identification of specific bacteria allows for targeted antibiotic therapy, improving outcomes and reducing the risk of antibiotic resistance. This test is particularly important for patients with fever of unknown origin, suspected septicemia, or those not responding to initial antibiotic treatment.
Frequently asked questions
Do I need to fast before this test?
How long does it take to get results?
Is the test painful?
What happens if my test is positive?
Can I have a negative result even if I have an infection?
Sources
- 1
- 2
- 3
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