Alpha<sub>1</sub>-Fetoprotein, Maternal Serum and Amniotic Fluid Synonyms AFP, Amniotic Fluid; Alpha-Fetoprotein, Amniotic Fluid

Laboratory Core Laboratory

Request Form General; special AFP Screening Form is required for maternal screening.

Phone (212) 305-8600

Availability Daily, 24 hours

Special Instructions The maternal serum and amniotic fluid AFP request form must be completed in order for the AFP test to be performed.

Specimen Amniotic fluid, maternal serum

Volume 20 mL amniotic fluid, full 6 mL gold top tube for serum

Minimum Volume 2 mL serum, 10 mL amniotic fluid

Container Sterile syringe for amniotic fluid, gold top tube for serum

Collection The optimal time to collect amniotic fluid for AFP is between the 16th and the 18th weeks of gestation. Include the approximate gestational age on the requisition. If the amniotic fluid is traumatic (bloody), a blood specimen should also be submitted. One or two drops of blood in amniotic fluid can give false-positive results.

Storage Instructions Store at room temperature until sent to the laboratory.

Patient Preparation Patient must avoid having radioisotope scan administered 24 hours prior to venipuncture.

Causes for Rejection Contamination of amniotic fluid with maternal or fetal blood, incorrect determination of gestational age, insufficient volume for test ordered, recently administered radioisotopes

Reference Range See report.

Use Analyze midtrimester amniotic fluid for detection of neural tube defects: anencephaly, spina bifida, myelocele, hydrocephaly

Methodology Immunoassay