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Cysteine in Cerebrospinal Fluid (CSF) – Mass Concentration

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

This test measures the amount of cysteine, an amino acid, in your cerebrospinal fluid (the fluid surrounding your brain and spinal cord). It may be used to assess metabolic or genetic conditions affecting amino acid metabolism.

Quick summary

["Cysteine levels in CSF can help diagnose or monitor certain inherited disorders."]

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

Key facts at a glance

LOINC
54336-3
Short code
Sulfocysteine CSF-sCnc
Synonyms
Sulfocysteine CSF-sCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Might This Test Be Ordered?

Your healthcare provider may recommend this test if you have symptoms or a family history suggestive of metabolic disorders, such as cystinosis or other aminoacidopathies. It could also be part of a broader evaluation for neurological symptoms linked to amino acid imbalances.

What Does the Test Involve?

A small amount of cerebrospinal fluid is collected via a procedure called a lumbar puncture (spinal tap). The fluid is then analyzed in a lab to measure cysteine levels.

What to Expect Before the Test

No special preparation is typically needed, but you may be asked to avoid certain medications or foods that could interfere with results. Discuss any medications with your provider before the test.

What to Expect During the Test

The procedure involves lying on your side with your back bent slightly. A needle is inserted into your lower back to collect CSF. You may feel pressure or a mild ache, but it usually doesn’t cause pain. The procedure takes about 10–15 minutes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cysteine CSF

Frequently asked questions

What Are Common Causes of Abnormal Results?
Abnormal cysteine levels in CSF are most commonly linked to inherited metabolic disorders (e.g., cystinosis). Other rare conditions or genetic mutations affecting amino acid metabolism could also cause variations. Always consult your healthcare provider to interpret results in the context of your medical history.
How Long Does It Take to Get Results?
Results are typically available within 1–3 business days, depending on lab processing times. Your provider will discuss the findings with you during a follow-up visit.
Can I Eat or Drink Normally Before the Test?
You can eat and drink as usual unless instructed otherwise by your provider. Avoid caffeine or alcohol before the lumbar puncture, as they may affect your comfort or procedure outcomes.
  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