During the first 10 weeks of life, the major serum protein is not albumin, but -fetoprotein (AFP). Fetal liver synthesizes huge quantities of AFP until about the 32nd week of gestation. Thereafter, synthesis declines until, at 1 year of age, the serum normally contains no more than 30 ng/mL.

Resting liver cells (hepatocytes) normally manufacture very little AFP, but rapidly multiplying hepatocytes resume synthesis of large amounts.⁴⁰ Thus, the test's greatest usefulness is in monitoring for recurrence of hepatic carcinoma or metastatic lesions involving the liver. Note that 30 to 50 percent of Americans with liver cancer do not have elevated AFP levels. More consistent elevations are seen in those Asian and African populations with a very high incidence of hepatocellular carcinoma.⁴¹

Measurement of AFP levels in maternal blood and amniotic fluid is used to detect certain fetal abnormalities, especially neural tube defects such as anencephaly, spina bifida, and myelomeningocele (see Chapter 10 - Amniotic Fluid Analysis). Routine prenatal screening includes determination of the mother's serum AFP level at 13 to16 weeks of pregnancy. If maternal blood levels are elevated on two samples obtained 1 week apart, an ultrasound may be performed, and AFP levels in amniotic fluid may be analyzed. Other possible causes of elevated AFP levels during pregnancy include multiple pregnancy and fetal demise.

• Monitoring for hepatic carcinoma or metastatic lesions involving the liver, as indicated by highly elevated levels (e.g., 10,000 to 100,000 ng/mL)
• Monitoring for response to treatment for hepatic carcinoma, with successful treatment indicated by an immediate drop in levels
• Monitoring for recurrence of hepatic carcinoma, with elevated levels occurring 1 to 6 months before the client becomes symptomatic
• Suspected hepatitis or cirrhosis, as indicated by slightly to moderately elevated levels (e.g., 500 ng/mL)
• Routine prenatal screening for fetal neural tube defects and other disorders, as indicated by elevated levels
• Suspected intrauterine fetal death, as indicated by elevated levels
• Support for diagnosing embryonal gonadal teratoblastoma, hepatoblastoma, and ataxia-telangiectasia

Nursing Care Before the Procedure

For serum studies, client preparation is the same as that for any study involving the collection of a peripheral blood sample (see Appendix I).

For amniotic fluid studies, the client is prepared for amniocentesis, as described in Chapter 10 - Amniotic Fluid Analysis.

For serum studies, a venipuncture is performed and the sample collected in a red-topped tube. The sample must be handled gently to avoid hemolysis and transported promptly to the laboratory. For amniotic fluid studies, amniocentesis is performed (see Chapter 10 - Amniotic Fluid Analysis).

Nursing Care After the Procedure

Care and assessment after the procedures are the same as for any study involving collection of a peripheral blood sample or amniocentesis (see Chapter 10 - Amniotic Fluid Analysis).

• Abnormal adult values: Note and report increased levels and relate to tissue healing or regeneration. Assess history for presence or treatment of malignancy; assist in coping with need for additional treatments.
• Abnormal fetal values: Note and report increased levels in amniotic fluid analysis results or pregnant woman's serum test results. Assess for fear and anxiety levels while waiting for test results. Provide information about genetic counseling, termination of pregnancy, or both.