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Direct Bilirubin, Amniotic Fluid — Spectrophotometry

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

This test measures direct bilirubin in amniotic fluid using spectrophotometry. It may be used to assess bilirubin accumulation related to red blood cell breakdown during pregnancy.

Quick summary

["Elevated bilirubin in amniotic fluid may suggest increased fetal red blood cell breakdown and requires clinical interpretation."]

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

Key facts at a glance

LOINC
27198-1
Short code
Bilirub Amn Spectrp dir-aCnc
Synonyms
Bilirub Amn Spectrp dir-aCnc
Category
liver
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
direct-spectrophotometry
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 laboratory test measures direct bilirubin, a yellow pigment produced during the breakdown of hemoglobin, in amniotic fluid. Spectrophotometry is used to estimate the amount of bilirubin in the sample.

Why might I need this test?

Amniotic fluid bilirubin testing may help evaluate suspected fetal red blood cell breakdown, including concerns related to blood-group incompatibility or hemolytic disease. It is usually ordered and interpreted by a pregnancy or fetal-medicine specialist.

How is the test performed?

Amniotic fluid is collected during an amniocentesis or, when appropriate, at delivery. The laboratory analyzes the fluid using spectrophotometry, and the result is interpreted together with other maternal and fetal test findings.

How do I prepare for the test?

This test depends on a clinical sample-collection procedure. Follow your healthcare professional's instructions about the procedure, and tell the care team about any relevant medications, allergies, or complications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Direct bilirubin, amniotic fluid

Frequently asked questions

Is this the same as a routine bilirubin blood test?
No. A routine bilirubin blood test measures bilirubin in the blood, while this test measures it in amniotic fluid. The results have different purposes and reference considerations.
Why is amniotic fluid collected?
Amniotic fluid is commonly obtained through amniocentesis when specific pregnancy or fetal concerns require testing. The procedure and its risks should be discussed with the healthcare professional recommending it.
Does an elevated result confirm a diagnosis?
No. It may support concern for increased fetal red blood cell breakdown, but it does not confirm hemolytic disease by itself. The full clinical picture and additional laboratory tests are needed.
  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