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Bacteriacsfcult

Published: August 9, 2026Updated: August 16, 2026

A laboratory test that detects and identifies bacteria in the fluid surrounding the brain and spinal cord to diagnose infections.

Quick summary

{"This test checks your cerebrospinal fluid (CSF) for bacterial infections","It helps diagnose meningitis, encephalitis, or other serious brain/spinal cord infections","Results typically take 2-5 days as bacteria need time to grow","A lumbar puncture (spinal tap) is required to collect the sample","Early detection is crucial for prompt treatment of serious infections"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
606-4
Short code
CSFBCID
Synonyms
Bacteria CSF Cult
Category
chemistry
Sample
csf
Container
Sterile screw-cap CSF collection tube (tube 1 for chemistry, tube 3 or 4 for microbiology) or sterile CSF transport container. Specimen should be collected directly into sterile tubes during lumbar puncture procedure.
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
culture
CPT
87070
SNOMED
42754008
Specimen volume
1-2 mL minimum; 3-5 mL preferred for optimal pathogen recovery. Larger volumes (up to 10 mL) recommended for adult patients to enhance recovery of fastidious organisms and mycobacteria.
Stability
Process immediately upon receipt. If delayed processing is unavoidable, store at room temperature (20-25°C) for no more than 2 hours. Do not refrigerate CSF for bacterial culture as refrigeration may inhibit growth of fastidious organisms like Neisseria meningitidis and Haemophilus influenzae. Specimen should ideally be transported to the laboratory within 1 hour of collection.
Hemolysis max
200
TAT
48–168 hours
Order
routine

What is this test?

The Cerebrospinal Fluid (CSF) Bacterial Culture is a diagnostic laboratory test that detects and identifies bacteria in the CSF—the clear, protective fluid that surrounds your brain and spinal cord. This test is crucial for identifying serious infections of the central nervous system.

How is the sample collected?

The CSF sample is collected through a procedure called a lumbar puncture, also known as a spinal tap. A healthcare provider inserts a thin needle into the lower back to extract CSF from the space around the spinal cord. This procedure is performed under sterile conditions to prevent contamination.

What happens during the test?

Once the CSF sample is collected, it is sent to a laboratory where it is placed in a special culture medium. Laboratory technicians observe the sample over several days to see if bacteria grow. If bacteria are detected, they are identified, and additional testing may be done to determine which antibiotics will be most effective for treatment.

Why might I need this test?

Your doctor may order this test if you have symptoms suggesting a brain or spinal cord infection, such as severe headache, fever, neck stiffness, confusion, or sensitivity to light. It is commonly used to diagnose meningitis (infection of the membranes surrounding the brain) or encephalitis (infection of the brain itself).

Reference range

No growth of pathogenic bacteria. Normal CSF is sterile. Any identification of bacteria from CSF is considered clinically significant and reported.N/A

Specimen: csf

No fasting required. Specimen collection requires strict aseptic technique via lumbar puncture under physician supervision. Discontinue antibiotics prior to collection when clinically possible, as prior antimicrobial therapy may yield false-negative results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

How long does it take to get results?
Results typically take 2-5 days because bacteria need time to grow in the laboratory culture. Preliminary results may be available sooner if bacteria are detected early.
Does a negative result mean I don't have an infection?
Not necessarily. A negative result could mean no bacterial infection is present, or the bacteria may be present in very low numbers that didn't grow in culture. Your doctor will interpret results alongside your symptoms and other test findings.
Is a lumbar puncture painful?
You may feel some discomfort or pressure during the procedure, but it is generally well-tolerated. A local anesthetic is used to numb the area. Some people may experience a headache afterward, which can usually be managed with rest and fluids.
What happens after a positive result?
If bacteria are identified, your healthcare team will determine the most appropriate antibiotic treatment based on the specific bacteria found and its sensitivity to various antibiotics. Treatment is typically started promptly, often before final results are available, based on clinical suspicion.
Are there risks to this test?
The main risks include headache, back pain, or bruising at the puncture site. More serious complications like infection or bleeding are rare. Your healthcare provider will discuss the risks and benefits with you before the procedure.
  1. 1
    Cerebrospinal Fluid (CSF) CultureSource
  2. 2
    Lumbar Puncture (Spinal Tap)Source
  3. 3
    Meningitis and EncephalitisSource

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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

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