Complete Blood Count (CBC) Test
A laboratory test that identifies and grows bacteria from a sample to diagnose infections and guide treatment.
{"This test finds what type of bacteria is causing your infection","It tests for both oxygen-loving (aerobic) and oxygen-hating (anaerobic) bacteria","Results help your doctor choose the right antibiotic","The sample is usually collected from the infected area","Results typically take 2-5 days"}
Key facts at a glance
- LOINC
- 21020-3
- Short code
- BACIDCUL
- Synonyms
- Bacteria Spec Anaerobe+Aerobe Cult
- Category
- chemistry
- Sample
- serum
- Container
- Anaerobic transport system (e.g., Anaerobic Transport Medium, Port-A-Cul vial) for anaerobic cultures; sterile container, swab in transport medium (Amies or Stuart's), or blood culture bottles for aerobic cultures. Specimen-specific containers may apply.
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- anaerobic-aerobic-culture
- CPT
- 87040; 87075; 87076; 87077; 87143; 87147; 87153; 87158
- SNOMED
- 104182005; 115515006
- Specimen volume
- Variable by specimen type; minimum 1 mL for fluid specimens; tissue specimens should be at least 1 cm³; blood cultures typically 8-10 mL per bottle (adult) or 1-3 mL (pediatric)
- Stability
- Anaerobic specimens: transport to laboratory within 2 hours at room temperature in anaerobic transport medium; hold at room temperature. Aerobic specimens: most stable at room temperature for up to 24 hours; refrigeration acceptable for urine and certain specimens. Do not refrigerate anaerobic specimens or those for fastidious organisms.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 48–672 hours
- Order
- routine
What is this test? A complete blood count (CBC) is a common blood test that measures the different cells in your blood, including red blood cells, white blood cells, and platelets, and helps evaluate your overall health.
A bacterial culture test is a laboratory procedure that allows doctors to identify the specific type of bacteria causing an infection. This test uses two methods: aerobic culture (for bacteria that need oxygen) and anaerobic culture (for bacteria that live without oxygen). By growing and identifying the bacteria, doctors can determine the exact cause of your infection and select the most effective treatment.
Why is it ordered? Your doctor may order a CBC as part of a routine checkup, to help diagnose conditions such as anemia, infection, or inflammation, to investigate symptoms like fatigue or unusual bleeding, and to monitor ongoing treatment.
Your doctor may order this test if you have signs of a bacterial infection, such as fever, swelling, pain, or discharge. It is commonly used for infections of wounds, blood, urine, respiratory tract, or other body areas. The test helps distinguish between bacterial and viral infections, which is important because antibiotics only work against bacteria, not viruses.
How is the sample collected? A small blood sample is drawn from a vein in your arm using a thin needle. The procedure takes only a few minutes, and you can usually return to your normal activities right afterward.
The sample depends on the type of infection suspected. For this test, a blood sample (serum) is taken from a vein in your arm. The procedure is quick and similar to other blood tests. In some cases, other samples like tissue, fluid, or swab from the infected area may also be collected. Follow your healthcare provider's instructions on how to prepare.
What do the results mean? Your results show whether your blood cell levels fall within normal ranges. Abnormal values may suggest conditions such as anemia, infection, or clotting problems, and your healthcare provider will explain what they mean for you.
A positive result means bacteria were found and identified in your sample. This confirms a bacterial infection and tells your doctor exactly which bacteria is causing it. A negative result means no bacteria were found, which could mean your infection is caused by something else (like a virus or fungus) or that the sample was collected before enough bacteria were present. Your doctor will interpret these results along with your symptoms and other tests.
Reference range
No growth of pathogenic bacteria. Results reported as organism identified or 'No growth' after standard incubation period.N/A
Specimen collection should be performed prior to initiation of antibiotic therapy when possible. Disinfect skin or mucosal surfaces with appropriate antiseptic (e.g., chlorhexidine, povidone-iodine) and allow to dry before collection to minimize contamination. Use aseptic technique throughout the collection process.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is crucial for diagnosing bacterial infections and guiding appropriate treatment. By identifying the specific bacteria, doctors can prescribe targeted antibiotics instead of broad-spectrum ones, which helps combat antibiotic resistance. It is particularly important for serious infections like sepsis, pneumonia, wound infections, and intra-abdominal infections. The test also helps determine whether anaerobic bacteria are involved, as these require special culture conditions and specific antibiotics.
Frequently asked questions
Does this test hurt?
How long does it take to get results?
Do I need to fast before this test?
What happens if the test is negative?
Do I need to stop antibiotics before the test?
Sources
- 1
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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