What it means
During pregnancy, some alpha-fetoprotein (AFP) passes from the fetus into the mother's blood. It is measured between about 15 and 20 weeks, alone or as part of the quad screen. A high level can point to an open neural tube defect such as spina bifida, an abdominal wall defect, twins or a wrong due date; a low level can point to a higher chance of Down syndrome. It is a screening test, so an abnormal result leads to more testing, such as ultrasound, not a diagnosis. In adults, a high level can be a sign of liver cancer or some testicular and ovarian tumors.
For the nurse
Explain that the test is a screen, not a diagnosis, and that an accurate due date matters for reading it. Support the client while follow-up tests are arranged.
At a glance
| Normal range | In pregnancy, results are reported against the average for that week of pregnancy (as multiples of the median), so each lab gives its own cutoffs. |
|---|---|
| Also written | AFP, maternal serum alpha-fetoprotein, MSAFP, alpha fetoprotein |
Related terms
ultrasound
An imaging test that uses high-frequency sound waves to make pictures of the inside of the body.
amniocentesis
A test in which a needle is put through the belly into the uterus to take a sample of amniotic fluid.