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Cystine in Amniotic Fluid (Mass Concentration)

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

This test measures the amount of cystine, an amino acid, in amniotic fluid. It is often used during pregnancy to assess for genetic conditions like cystic fibrosis.

Quick summary

["This test helps evaluate potential genetic disorders in your baby."]

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

Key facts at a glance

LOINC
27027-2
Short code
Cystine Amn-sCnc
Synonyms
Cystine Amn-sCnc
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may recommend this test if you are at higher risk for cystic fibrosis or other genetic conditions affecting amino acid metabolism. It is typically performed during prenatal screening or diagnostic testing when amniotic fluid is collected for further analysis.

What Does the Test Involve?

Amniocentesis is a procedure where a small amount of amniotic fluid is extracted from your uterus through a needle. The fluid is then analyzed in a lab to measure cystine levels. This procedure is usually done under ultrasound guidance and is generally safe with minimal risk.

What Are the Possible Results?

Results are interpreted by medical professionals in the context of your overall health and family medical history. Elevated cystine levels in amniotic fluid may suggest conditions like cystic fibrosis, but further genetic testing is often required for confirmation.

What Are the Risks?

While amniocentesis is considered safe, there are minor risks such as infection, preterm labor, or a very rare chance of miscarriage. Your healthcare provider will discuss these risks with you before the procedure.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Amniotic Fluid Cystine Level

Frequently asked questions

What Does It Mean If My Results Are Abnormal?
Abnormally high cystine levels in amniotic fluid can indicate genetic disorders such as cystic fibrosis. This finding prompts further genetic testing to confirm the diagnosis and guide appropriate prenatal care or interventions.
How Often Is This Test Performed?
This test is usually performed once during pregnancy, typically between 15 and 20 weeks, depending on the clinical indication. It is not a routine screening test for all pregnancies but is recommended for those with a higher risk of genetic conditions.
Can I Avoid This Test?
If you have a family history of cystic fibrosis or other genetic disorders, your healthcare provider may recommend this test to assess your baby’s risk. Discuss your preferences and concerns with your provider to understand the benefits and risks involved.
  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