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Cerebrospinal Fluid (CSF) Vitamin B12 (Cobalamin) Concentration

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

This test measures the level of vitamin B12 in your cerebrospinal fluid, which surrounds the brain and spinal cord.

Quick summary

["Vitamin B12 in CSF helps assess neurological health and potential deficiencies affecting the central nervous system."]

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

Key facts at a glance

LOINC
22245-5
Short code
CMV IgG Titr CSF
Synonyms
CMV IgG Titr CSF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Ref low
8
Ref high
61
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82977
SNOMED
3110003
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like numbness, tingling, balance issues, or cognitive problems that could be linked to vitamin B12 deficiency. It may also be used to evaluate conditions affecting the central nervous system, such as multiple sclerosis or other neurological disorders.

What to Expect Before the Test

No special preparation is needed. You may have a spinal tap (lumbar puncture) where a small amount of CSF is collected from your lower back. This procedure is usually done in a hospital or clinic setting and may cause mild discomfort.

What the Results Mean

Low levels of vitamin B12 in CSF can indicate neurological damage or deficiency, while higher levels may suggest certain inflammatory or infectious conditions of the central nervous system. Your results will be interpreted by your healthcare provider in the context of your overall health and symptoms.

Common Conditions Monitored

This test is often used to diagnose or monitor conditions like vitamin B12 deficiency, multiple sclerosis, Guillain-Barré syndrome, or other neurological disorders affecting the central nervous system.

Reference range

Adult males: 8-61 U/L; Adult females: 5-36 U/LN/A

Specimen: csf

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CSF B12

Frequently asked questions

What are the normal reference ranges for this test?
Reference ranges can vary by lab and may not be widely standardized for CSF vitamin B12. Your healthcare provider will use clinical judgment to interpret your results based on your symptoms, medical history, and other test results.
Why might my vitamin B12 levels in CSF be different from my blood vitamin B12 levels?
Vitamin B12 in CSF is distinct from blood levels because it reflects the vitamin’s availability in the central nervous system. Blood tests measure overall vitamin B12 status, while CSF tests focus on neurological exposure. Your provider may order both for a comprehensive evaluation.
Can diet or supplements affect this test?
Dietary intake or supplements of vitamin B12 may influence blood levels but are less likely to directly affect CSF levels. Since CSF is collected directly from the central nervous system, external factors like diet have minimal direct impact on this specific test result.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

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