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Glucose in Cerebrospinal Fluid (CSF)

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

This test measures the amount of glucose (sugar) found in your cerebrospinal fluid, which surrounds your brain and spinal cord. It helps assess how well your brain is receiving nutrients and detecting potential issues like infections or inflammation.

Quick summary

["A low CSF glucose level may signal serious conditions requiring medical evaluation."]

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

Key facts at a glance

LOINC
14744-7
Short code
Glucose CSF-sCnc
Synonyms
Glucose CSF-sCnc
Category
glucose
Sample
csf
Container
Sterile tube
Units
N/A
Ref low
70
Ref high
100
Critical range
50 N/A – 400 N/A
Fasting
true
Population
adult
Sex
all
Age range
18–65 years
CPT
82947
SNOMED
260395008
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test if you have symptoms like severe headaches, neck stiffness, fever, or neurological concerns. It’s also used to diagnose or monitor conditions such as meningitis, encephalitis, or other brain infections/inflammations.

What to Expect Before the Test

No special preparation is needed. The test involves a simple spinal tap (lumbar puncture) where a small amount of CSF is collected via a needle. You may feel mild pressure or discomfort, but it’s usually brief.

What Happens During the Test?

A healthcare professional will insert a needle into your lower back to collect CSF. The sample is then sent to the lab for glucose measurement. The process takes about 15–30 minutes.

What Are Possible Results?

Results are compared to standard reference ranges for CSF glucose. Abnormally low levels may indicate infections, autoimmune diseases, or other neurological conditions. High levels could suggest metabolic disorders or rare genetic conditions.

Reference range

Fasting: 70-100 mg/dLN/A

Specimen: csf

Fasting for 8-12 hours required. Water is permitted. Avoid chewing gum and smoking before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Low CSF Glucose Levels Can Indicate Serious Conditions

Short name

CSF Glucose

Frequently asked questions

What Causes Low CSF Glucose?
Low CSF glucose is most commonly linked to bacterial or fungal meningitis, encephalitis, or subarachnoid hemorrhages. It may also occur in conditions like multiple sclerosis or certain metabolic disorders.
What Causes High CSF Glucose?
Elevated CSF glucose is less common but can occur in viral meningitis, certain tumors, or metabolic disorders like diabetes. Rarely, it may reflect a breakdown in the blood-brain barrier.
How Often Is This Test Repeated?
Your provider may repeat this test if initial results are abnormal or if symptoms persist. Follow-up may include additional imaging, cultures, or other diagnostic tests.
  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