Chromosome, AFP/AChE/HbF, Amn
Chromosome Analysis, AFP, AChE, Amniotic Fluid With Reflex to Fetal Hemoglobin (Hb F)
Determine fetal karyotype; prenatal diagnosis of Down syndrome or other chromosomal abnormalities; analysis of midtrimester amniotic fluid for detection of open neural tube and ventral wall defects
20 to 30 mL
Sterile plastic conical tube; do not use urine containers or tubes with rubber stoppers. Rubber is toxic to amniocytes.
Discard first 2 mL of fluid aspirated to avoid maternal cell contamination. Specimen is collected in a 20 mL sterile syringe and transferred aseptically to sterile tubes. The test request form is completed and accompanies specimen and miscellaneous slip to the laboratory.
Maintain specimen at room temperature. Do not freeze or refrigerate.
Specimen found not to be amniotic fluid; gross contamination with red cells; frozen specimen; nonsterile container. Do not use urine containers or tubes with rubber stoppers; rubber is toxic to amniocytes.