Alpha-fetoprotein (AFP) is a protein normally produced by the fetal liver and yolk sac that is the major fetal serum protein. AFP levels are measured in pregnancy screening to assess the risk of birth defects like neural tube defects or chromosomal abnormalities. Elevated AFP may indicate fetal body wall defects where the protein leaks into the amniotic fluid and mother's blood. Low AFP can suggest Down syndrome risk. AFP is also measured as a tumor marker, as increased levels indicate hepatocellular carcinoma or germ cell tumors of the ovaries and testes.

1. ALPHA1-FETOPROTEIN
PRAKASH MISHRA

2. INTRODUCTION
 Alpha-fetoprotein (AFP) is an oncofetal protein
 Which normally produced by the fetal liver and yolk sac.
 It is the major fetal serum protein (analogous to serum albumin in adults).
 The dominant fetal serum protein in the first trimester of life and diminishes to very
low levels by the age of 1 year.
 AFP appears in the amniotic fluid from fetal urination.
 Its amniotic fluid concentration parallels fetal serum levels, except that the amniotic
fluid level is about 150 times lower in concentration.
 Through placental transfer, AFP also appears in maternal serum.

3. INDICATIONS
 This test is used as a screening marker indicating
increased risk for birth defects, such as fetal body
wall defects, neural tube defects, and
chromosomal abnormalities.
 It can also be used as a tumor marker to identify
cancers.

4.  AFP is an effective screening serum marker for fetal body wall
defects
 If a fetus has an open body wall defect, fetal serum AFP leaks
out into the amniotic fluid and is picked up by the maternal
serum.
 Normally detect in mother’s blood after 10 weeks’ gestation.
 Peak levels occur between 16 and 18 weeks.

5.  Elevated serum AFP levels in pregnancy may also indicate
multiple pregnancy, fetal distress, fetal congenital
abnormalities, or intrauterine death.
 The overlap in AFP values between unaffected and affected
pregnancies,
 The test is not diagnostic and requires confirmatory
diagnostic procedures (e.g., acetylcholinesterase and AFP
levels in the amniotic fluid, and high-resolution
ultrasonography).

6.  Low levels of maternal serum AFP may also be informative in
assessing other fetal abnormalities such as down’s syndrome.
 Some of the salient features of down’s syndrome include trisomy 21,
malformations, dysmorphic features, and mental retardation.
 The risk of down ’ s syndrome increases with maternal age.
 At age 35, the risk at birth is 1 in 385, and at age 40 it is 1 in 105.
 In estimating the risk of down ’ s syndrome, three other biochemical
serum parameters in addition to AFP are measured:
 Unconjugated estriol (which is decreased);
 Human chorionic gonadotropin (hcg, which is increased);
 Inhibin A (which is elevated).

7.  Serum AFP levels are elevated in hepatocellular carcinomas and
malignancies involving the ovaries and testes.
 Yolk sac tumors, which occur more frequently in the ovaries of
young women and girls, and in the testes of boys, raise serum
levels of AFP.
 Serum hCG measurement is also helpful in the diagnosis and
management of germ cell tumors.
 Thus, hCG and AFP are also used as tumor markers

8. AFP is also used as a tumor marker. Increased serum
levels of AFP are found in as many as 90% of patients
with hepatomas.
The higher the AFP level, the greater the tumor
burden.
A decrease in AFP is seen if the patient is responding
to antineoplastic therapy.

9.  It also increase in malignancies involving the ovaries and
testes.
 Yolk sac tumors, which occur more frequently in the
ovaries of young women and girls, and in the testes of
boys, raise serum levels of AFP.
 Serum hCG measurement is also helpful in the diagnosis
and management of germ cell tumors.
 Thus, hCG and AFP are also used as tumor markers

10. NORMAL FINDINGS
 Adult: <40ng/mL or <40mcg/L (SI units)
 Child (<1 year): <30ng/mL
(Ranges are stratified by weeks of gestation and vary
according to laboratory.)
Testing methods for AFP quantifcation include radioimmunoassay or
enzyme-linked immunosorbent assay (ELISA) with a commercially
available kit.

11. ABNORMAL FINDINGS
Increased maternal
AFP levels
 Neural tube defects (e.g., anencephaly,
encephalocele, spina bifida,
myelomeningocele)
 Abdominal wall defects(If a fetus has an
open body wall defect, fetal serum AFP
leaks out into the amniotic fluid and is
picked up by the maternal serum)
 Multiple pregnancy (multiple fetuses make
large quantities)
 Threatened abortion
 Fetal distress orcongenital anomalies
 Fetal death
Decreased maternal serum
AFP levels
 Trisomy 21 (Down
syndrome)
 Fetal wastage

12. Increased nonmaternal A AFP levels
 Primary hepatocellular cancer (hepatoma)
 Germ cell or yolk sac cancer of the ovary
 Embryonal cell or germ cell tumor of the testes
 Other cancers (e.g.,stomach, colon, lung, breast, or
lymphoma)
 Liver cell necrosis (e.g., cirrhosis or hepatitis)

13. THANK YOU