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Test ID AFBIL Bilirubin, Amniotic Fluid

Reporting Name

Bilirubin, AF

Useful For

Evaluation of Rh disease, ie, hemolytic disease of the fetus

 

Monitoring disease progression to assess need for fetal transfusion

Specimen Type

Amniotic Fld


Shipping Instructions


Ship specimen in amber vial to protect from light.



Necessary Information


Gestational age at time of amniocentesis is required.



Specimen Required


Supplies: Amber Frosted Tube, 5 mL (T192)

Collection Container/Tube: Amniotic fluid container

Submission Container/Tube: Opaque, amber vial (T192)

Specimen Volume: 3.5 mL

Collection Instructions:

1. Centrifuge, separate supernatant, and send both supernatant and sediment.

2. Label specimens as sediment and supernatant.


Specimen Minimum Volume

1.7 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Amniotic Fld Frozen 70 days LIGHT PROTECTED

Reference Values

Interpretation of fetal risk is dependent upon gestational age.

Refer to either the Queenan Curve (gestational age <27 weeks) or the Liley Chart (gestational age >27 weeks) listed under Interpretation of Amniotic Fluid Bilirubin Results (Delta OD 450) in Special Instructions.

Day(s) and Time(s) Performed

Monday through Saturday; Continuously

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82247

LOINC Code Information

Test ID Test Order Name Order LOINC Value
AFBIL Bilirubin, AF 12476-8

 

Result ID Test Result Name Result LOINC Value
AMBL Amniotic Fluid 12476-8
AFCMT Other Information 48767-8
GSTN Gestation 18185-9

Clinical Information

The presence of bilirubin in amniotic fluid, which results in a yellow color, is an indicator of fetal erythroblastosis. Visual inspection of amniotic fluid is unreliable because bilirubin is not the only cause of an excessive yellow color; therefore, the presence of bilirubin must be confirmed with spectrophotometric methods. Meconium may contribute a green color (biliverdin) that can obscure the color of bilirubin and hemoglobin.

Interpretation

The reference range for bilirubin in amniotic fluid is related to the gestational age of the fetus. Refer to either the Queenan Curve (gestational age <27 weeks) or the Liley Chart (gestational age >27 weeks) listed under Interpretation of Amniotic Fluid Bilirubin Results (Delta OD 450) in Special Instructions.

Clinical Reference

1. Scott F, Chan FY: Assessment of the clinical usefulness of the 'Queenan' chart versus the 'Liley' chart in predicting severity of rhesus iso-immunization. Prenat Diagn 1998;18:1143-1148

2. Liley AW: Liquor amnii analysis in the management of the pregnancy complicated by rhesus sensitization. Am J Obstet Gynecol 1961;82:1359-1370

Analytic Time

Same day

Method Name

Spectrophotometric Scan