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Test Code AFPA Alpha-Fetoprotein, Amniotic Fluid

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
ACHE_ Acetylcholinesterase, AF Yes No

Testing Algorithm

If alpha-fetoprotein is positive, then acetylcholinesterase will be performed at an additional charge.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Amniotic Fld


Necessary Information


The following information is required:

1. Estimated due date by ultrasound

2. Collection date

3. Gestational age must be between 13 and 24 weeks; 16 to 18 weeks preferred.

 

If not ordering electronically, provide information on Second Trimester Maternal Screening Alpha-Fetoprotein / Quad Screen Patient Information (T595) and send with specimen.



Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Container/Tube: Plain, plastic, screw-top tube

Specimen Volume: 0.75 mL

Collection Instructions: Do not centrifuge.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Amniotic Fld Refrigerated (preferred) 7 days
  Ambient  7 days

Reference Values

< 2.0 multiples of median (MoM)

Day(s) Performed

Monday through Friday

CPT Code Information

82106

82013 (if appropriate)

Clinical Information

Alpha-fetoprotein (AFP) is a single polypeptide chain glycoprotein with a molecular weight of approximately 70,000 Da. Synthesis of AFP occurs primarily in the liver and yolk sac of the fetus. It is secreted in fetal serum, reaching a peak at approximately 13 weeks gestation, after which it rapidly declines until about 22 weeks gestation and then gradually declines until term. Transfer of AFP into maternal circulation is accomplished primarily through diffusion across the placenta. Maternal serum AFP levels rise from the normal non-pregnancy level of 0.20 ng/mL to about 250 ng/mL at 32 weeks gestation.

 

If the fetus has an open neural tube defect, AFP is thought to leak directly into the amniotic fluid, causing unexpectedly high concentrations of AFP. Other fetal abnormalities such as omphalocele, gastroschisis, congenital kidney disease, and esophageal atresia; and other fetal distress situations such as threatened abortion, prematurity, and fetal demise, may also show AFP elevations. Decreased amniotic fluid AFP values may be seen when gestational age has been overestimated.

Report Available

2 to 19 days

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Method Name

AFPA: Immunoenzymatic Assay

ACHE_: Polyacrylamide Electrophoresis