α-Fetoprotein (AFP), Amniotic Fluid

Casandra

Casandra Test Code LC66940Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 002428CPT Code 82106

α-Fetoprotein (AFP), Amniotic Fluid

Also known as: AFP, Amniotic Fluid, Alpha-Fetoprotein (AFP), Amniotic Fluid, Amniotic Fluid AFP

Clinical Use

Order Test

Use

Analysis of midtrimester amniotic fluid for detection of open neural tube defects and ventral wall defects

Special Instructions

Include the gestational age by ultrasound and/or last menstrual period (LMP) on the request form on the date of draw of the sample. The patient's gestational age must be between 12 weeks and 24 weeks for interpretation of α-fetoprotein. Note that AChE false-positive and false-negative results are more frequent at gestational ages less than 13 weeks or greater than 24.9 weeks. Optimal gestational age is 14 to 18 weeks.

Limitations

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration. The interpretation of AFP levels can be influenced by factors such as contamination of amniotic fluid with blood, and the gestational age is critical to accurate interpretation. False positives or negatives in acetylcholinesterase results are more frequent at gestational ages less than 13 weeks or greater than 24.9 weeks.

Test Details

Methodology

Immunoassay (CLIA)

Biomarkers

Targets summarized.

AcetylcholinesteraseAFPAFP MoMFetal HemoglobinGestational Age (Wks)Interpretation

LOINC Codes

Order Codes

58735-2

Result Codes

1832-5
29253-2
49051-6
41273-4
72486-4
30106-9
28067-7
76479-5

Result Turnaround Time

2-5 days

Specimen

Amniotic Fluid

Volume

1 mL

Minimum Volume

Not provided

Container

Sterile plastic conical tube; do not use urine containers or tubes with rubber stoppers. Rubber is toxic to amniocytes.

Collection Instructions

Avoid contamination of amniotic fluid with maternal or fetal blood. As little as one drop of fetal blood can cause false-positive results during assay. Amniotic fluid should be collected by the attending physician.

Patient Preparation

The patient should have undergone ultrasound studies to verify fetal viability, detect multiple gestation, confirm gestational age, localize placenta and detect fetal and uterine pathology.