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Fetal Blood Contamination, Amniotic Fluid (FBC-R)
Bovine Serum Contamination, Amniotic Fluid (BSA-R)
Counterimmunoelectrophoresis and radialimmunodiffusion
Prenatal Screening Laboratory
Specimen Required:
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Amniotic fluid: 1 mL
Include 1 mL whole fluid if visibly bloody
Room temperature or 4°C
| Days Test Set Up:
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FBC - Monday-Thursday
BSA - Friday.
| Analytic Time:
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24 hours
| Reference Values:
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No precipitin band = Normal
| CPT Code(s):
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86331, 86185
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Relevance
The presence of fetal serum in amniotic fluid can contribute to elevated amniotic fluid alpha-fetoprotein or positive acetylcholinesterase (AChE).
Notes
The presence of fetal bovine serum albumin (BSA), another cause of false positive AChE results, can be confirmed with this same method.
Reference(s)
- Wald NJ, Cuckle HS, Nanchahal K: Amniotic fluid acetylcholinesterase measurement in the prenatal diagnosis of open neural tube defects. Second report of the collaborative acetylcholinesterase study. Prenat Diagn, 9:813-827, 1989.
- Barlow RD, Cuckle HS, Wald NJ, et al.: False positive gel-acetylcholinesterase results in blood-stained amniotic fluids. Br J Obstet Gynæcol, 89:821, 1982.
- Doran TA, Allen LC, Pirani BBK, et al.: False positive amniotic fluid alpha-fetoprotein levels resulting from contamination with fetal blood: Results of an experiment. Am J Obstet Gynecol, 127:799, 1977.
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