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# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Alpha-Fetoprotein, Amniotic Fluid (AFPA)
Test Code: AFAFPSO
Synonyms/Keywords

​Ref Lab Code: 9950, AFP (Alpha-Fetoprotein), AFP-AF (Alpha-Fetoprotein, Amniotic Fluid), Alpha Fetoprotein, Amniotic Fluid, Alpha-Fetoprotein, Amniotic Fluid, Fetoprotein, Amniotic Fluid

Useful For
​Screening for open neural tube defects or other fetal abnormalities
 
Follow-up testing for patients with elevated serum alpha-fetoprotein results or in conjunction with cytogenetic testing
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Amniotic fluid​ Amniotic fluid container​ 1 mL​ 0.5 mL​
Collection Processing Instructions
1. The following information is required:
a. Date ultrasound performed
b. Estimated due date by ultrasound
c. Collection date
d. Gestational age must be between 13 and 24 weeks; 16 to 18 weeks preferred.
2. If chromosome studies are also requested, see AF/8426 Chromosome Analysis, Amniotic Fluid. The specimen for AFP-AF testing, when requested with chromosome analysis, cannot be frozen.
Forms: Second Trimester Maternal Screening Alpha-Fetoprotein (AFP)/QUAD Screen Patient Information Sheet  is required in Special Instructions
Specimen Stability Information
Specimen Type Temperature Time
Amniotic Fld​ Refrigerated​ 7 days​
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Medical Laboratories
Monday through Friday​
2 days​
AFPA/9950: Immunoenzymatic Assay
ACHE_/9287: Polyacrylamide Electrophoresis​
Reference Lab
Reference Range Information
< or = 2.0 multiples of median (MOM) gestational group.
Interpretation
​A diagnostic alpha-fetoprotein (AFP) cutoff level of 2.0 multiples of median (MoM), followed by acetylcholinesterase (AChE) confirmatory testing on positive results, is capable of detecting 96% of open spina bifida cases with a false-positive rate of only 0.06% in non blood-stained specimens.
 
AChE analysis is an essential confirmatory test for all amniotic fluid specimens with positive AFP results. Normal amniotic fluid does not contain AChE, unless contributed by the fetus as a result of open communication between fetal central nervous system (eg, open neural tube defects), or to a lesser degree, fetal circulation. All amniotic fluid specimens testing positive for AFP will have the AChE test performed. Because false-positive AChE may occur from a bloody tap, specimens with positive AChE results will also be tested for the presence of fetal hemoglobin, which may cause both elevated AFP and AChE levels.
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​82106
​82013 ​1 ​Acetylcholinesterase ​If needed
Synonyms/Keywords

​Ref Lab Code: 9950, AFP (Alpha-Fetoprotein), AFP-AF (Alpha-Fetoprotein, Amniotic Fluid), Alpha Fetoprotein, Amniotic Fluid, Alpha-Fetoprotein, Amniotic Fluid, Fetoprotein, Amniotic Fluid

Ordering Applications
Ordering Application Description
​Centricity ​Amnio Alpha-Fetoprotein
​Cerner ​Alpha Fetoprotein Amniotic Fluid (AFPA)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Amniotic fluid​ Amniotic fluid container​ 1 mL​ 0.5 mL​
Collection Processing Instructions
1. The following information is required:
a. Date ultrasound performed
b. Estimated due date by ultrasound
c. Collection date
d. Gestational age must be between 13 and 24 weeks; 16 to 18 weeks preferred.
2. If chromosome studies are also requested, see AF/8426 Chromosome Analysis, Amniotic Fluid. The specimen for AFP-AF testing, when requested with chromosome analysis, cannot be frozen.
Forms: Second Trimester Maternal Screening Alpha-Fetoprotein (AFP)/QUAD Screen Patient Information Sheet  is required in Special Instructions
Specimen Stability Information
Specimen Type Temperature Time
Amniotic Fld​ Refrigerated​ 7 days​
Useful For
​Screening for open neural tube defects or other fetal abnormalities
 
Follow-up testing for patients with elevated serum alpha-fetoprotein results or in conjunction with cytogenetic testing
Reference Range Information
< or = 2.0 multiples of median (MOM) gestational group.
Interpretation
​A diagnostic alpha-fetoprotein (AFP) cutoff level of 2.0 multiples of median (MoM), followed by acetylcholinesterase (AChE) confirmatory testing on positive results, is capable of detecting 96% of open spina bifida cases with a false-positive rate of only 0.06% in non blood-stained specimens.
 
AChE analysis is an essential confirmatory test for all amniotic fluid specimens with positive AFP results. Normal amniotic fluid does not contain AChE, unless contributed by the fetus as a result of open communication between fetal central nervous system (eg, open neural tube defects), or to a lesser degree, fetal circulation. All amniotic fluid specimens testing positive for AFP will have the AChE test performed. Because false-positive AChE may occur from a bloody tap, specimens with positive AChE results will also be tested for the presence of fetal hemoglobin, which may cause both elevated AFP and AChE levels.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Medical Laboratories
Monday through Friday​
2 days​
AFPA/9950: Immunoenzymatic Assay
ACHE_/9287: Polyacrylamide Electrophoresis​
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​82106
​82013 ​1 ​Acetylcholinesterase ​If needed
For most current information refer to the Marshfield Laboratory online reference manual.