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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) in your cerebrospinal fluid (the fluid surrounding your brain and spinal cord). It helps assess conditions like meningitis, brain infections, or other neurological issues.

Quick summary

["Glucose levels in CSF can indicate infections, inflammation, or other brain-related problems."]

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

Key facts at a glance

LOINC
76669-1
Short code
Glucose tube1 CSF-sCnc
Synonyms
Glucose tube1 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, fever, confusion, or neurological concerns. It’s also used to monitor conditions like meningitis, encephalitis, or subarachnoid hemorrhage.

What to Expect Before the Test

No special preparation is needed. The test involves a simple spinal tap (lumbar puncture) where a small needle collects CSF from your lower back. You may feel pressure or mild discomfort, but it’s usually quick and painless.

What Happens During the Test?

A healthcare provider will insert a needle into your back to collect CSF into a sterile tube. The sample is then sent to the lab for glucose measurement using a specialized method.

What Are Normal Results?

Normal results vary by lab, but typically, glucose in CSF should be lower than in your bloodstream. Abnormally high or low levels may signal infections, bleeding, or other issues.

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

Why might my glucose levels in CSF be different from my blood glucose?
CSF glucose is often lower than blood glucose due to its role in protecting the brain. However, infections (like bacterial meningitis) can cause a drop, while bleeding or inflammation may raise it. Always discuss results with your doctor.
What symptoms might indicate abnormal CSF glucose?
Symptoms like severe headaches, fever, neck stiffness, confusion, or vision changes could suggest abnormal CSF glucose, especially if paired with other neurological signs. Your doctor will consider your full medical history and test results.
How often should I get this test?
Your doctor will determine frequency based on your symptoms, diagnosis, or ongoing condition. Regular monitoring may be needed if you have chronic neurological issues or recent infections.
  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