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7-Dehydrocholesterol, Amniotic Fluid — Tandem Mass Spectrometry

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

Measures 7-dehydrocholesterol in amniotic fluid to help evaluate a fetus for Smith-Lemli-Opitz syndrome or related cholesterol metabolism disorders.

Quick summary

["Abnormally low 7-dehydrocholesterol may indicate a cholesterol metabolism disorder such as Smith-Lemli-Opitz syndrome."]

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

Key facts at a glance

LOINC
109560-3
Short code
7-DHC Msmt Amn
Synonyms
7-DHC Msmt Amn
Category
lipid
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

What is this test?

This test measures the amount of 7-dehydrocholesterol, a substance involved in cholesterol production, in amniotic fluid. It can help evaluate certain inherited disorders of cholesterol metabolism during pregnancy.

Why might I need this test?

This test may be considered when ultrasound findings suggest a possible birth defect or when there is a family history of Smith-Lemli-Opitz syndrome. It is usually performed after discussion with a genetic counselor or maternal-fetal medicine specialist.

How is the test performed?

A clinician collects amniotic fluid through amniocentesis. The laboratory then measures 7-dehydrocholesterol using tandem mass spectrometry, which separates and identifies molecules in the sample.

How do I prepare for the test?

No food or medicine restrictions are generally required for the laboratory analysis. You will receive specific instructions about amniocentesis, including when to arrive and how the procedure will be managed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Amniotic fluid 7-dehydrocholesterol

Frequently asked questions

Does this test diagnose Smith-Lemli-Opitz syndrome by itself?
No. The result is one part of the evaluation and may need to be confirmed with genetic testing and clinical findings.
How is amniotic fluid collected?
A trained clinician performs amniocentesis using ultrasound guidance to locate the amniotic sac and remove a small amount of fluid.
Is there any special preparation for the laboratory test?
There is usually no separate preparation for the laboratory measurement. Follow the procedure-specific instructions provided by the clinician performing the amniocentesis.
  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