α-Fetoprotein (AFP), Amniotic Fluid
Also known as: AFP, Amniotic Fluid, Alpha-Fetoprotein (AFP), Amniotic Fluid, Amniotic Fluid AFP
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.
Methodology
Immunoassay (CLIA)
Biomarkers
LOINC Codes
- 58735-2
- 1832-5
- 29253-2
- 49051-6
- 41273-4
- 72486-4
- 30106-9
- 28067-7
- 76479-5
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
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.
Storage Instructions
Ship and maintain specimen at room temperature.
Causes for Rejection
Specimen not amniotic fluid; gross contamination of amniotic fluid with maternal or fetal blood; quantity not sufficient for analysis