Test ID AFBIL Bilirubin, Amniotic Fluid
Reporting Name
Bilirubin, AFUseful For
Evaluation of Rh disease, ie, hemolytic disease of the fetus
Monitoring disease progression to assess need for fetal transfusion
Specimen Type
Amniotic FldShipping 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 |
Special Instructions
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 dayMethod Name
Spectrophotometric Scan