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Glucose in Cerebrospinal Fluid (CSF) by Substance Concentration

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

This test measures the amount of glucose (sugar) found in your cerebrospinal fluid (the fluid surrounding your brain and spinal cord). It helps assess conditions affecting the blood-brain barrier or central nervous system.

Quick summary

["Glucose levels in CSF can indicate issues like infections, inflammation, or blood flow problems in the brain."]

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

Key facts at a glance

LOINC
76672-5
Short code
Glucose tube4 CSF-sCnc
Synonyms
Glucose tube4 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 doctor may order this test if you have symptoms like severe headaches, neck stiffness, confusion, or signs of neurological problems. It’s also used to monitor conditions such as meningitis, encephalitis, or subarachnoid hemorrhage, where abnormal glucose levels can signal underlying causes.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or back to draw a small amount of CSF, usually through a procedure called a lumbar puncture (spinal tap). The test is quick but may cause mild discomfort.

What Happens During the Test?

A healthcare provider will insert a needle into your lower back to collect fluid from the spinal canal. The fluid is then sent to the lab for testing, including measuring glucose concentration.

What Are Possible Results?

Results are compared to standard ranges for CSF glucose, though exact values can vary by lab. Low levels may suggest infections (like meningitis), while high levels could indicate bleeding into the CSF or other 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.

◆Associated findings1

Short name

CSF Glucose

Frequently asked questions

Will I need to avoid certain foods or drinks before the test?
No special diet or restrictions apply. However, inform your doctor if you’re taking medications that might affect glucose levels, such as diabetes medications.
How long will it take to get my results?
Results are typically available within 24 to 48 hours, depending on lab processing times. Your doctor will contact you once they’re ready for discussion.
Can I have a follow-up test if my initial result is abnormal?
Yes, if your result is outside expected ranges, your doctor may recommend additional tests or further evaluation to determine the cause, such as repeat CSF analysis or imaging studies.
  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