A nurse is handling a pregnant client who was prescribed to have an Alpha Fetoprotein level. The nurse should explain to client that this blood test:

Correct Answer: C. Once the Alpha-Fetoprotein levels are abnormal, amniocentesis will be ordered.

If the Alpha-Fetoprotein levels are abnormal, the physician will prescribe amniocentesis to confirm or eliminate the diagnosis of a neural tube defect. Alpha-fetoprotein (AFP) is a plasma protein produced by the embryonic yolk sac and the fetal liver. AFP levels in serum, amniotic fluid, and urine function as a screening test for congenital disabilities, chromosomal abnormalities, as well as some other adult occurring tumors and pathologies.

• Option A: Option A is incorrect since Alpha Fetoprotein does not indicate lung disorders. It is pertinent to explain that this is a screening test. Depending on the outcome, more tests may be ordered for the purpose of establishing a diagnosis. A negative test does not necessarily indicate no risk as very low maternal blood alpha-fetoprotein is associated with an increased incidence of Down syndrome.
• Option B: Option B is incorrect because an increase of human chorionic gonadotropin instead is associated with an increased risk for chromosome abnormality. This tumor marker is a glycoprotein encoded by the AFP gene on chromosome 4q25. Prenatal levels in developing human embryos rise from the end of the first trimester and begin to fall after 32 weeks of gestation. Maternal serum AFP forms part of the triple or quadruple screening tests for fetal anomaly.
• Option D: Option D is incorrect because an Alpha Fetoprotein level is a screening test and is not a definitive test. This tumor marker is a glycoprotein encoded by the AFP gene on chromosome 4q25. Prenatal levels in developing human embryos rise from the end of the first trimester and begin to fall after 32 weeks of gestation. Maternal serum AFP forms part of the triple or quadruple screening tests for fetal anomaly.