Medical Terminology: Pregnancy and Genetics Tests

1. What are Pregnancy and Genetics Tests?
Health care providers have an arsenal of tests that provide clues to the underlying cause of infertility and risk for genetic disorders that can affect the fetus or newborn. There are screening tests whose purpose is to assess if the patient is at risk for a disease, and diagnostic tests that are used to determine if the patient has a disease. These tests are ordered to screen patients for disorders when there are no telltale signs or symptoms and other tests are ordered when the health care provider is looking to confirm a sign or symptom that something is outside the normal parameters.
These tests look for certain components in blood such as the presence of antibodies or certain enzymes or the levels of protein and hormones. Scientific research has determined that the absence or existence of these components in blood correlates to the presence or absence of a specific disorder.

2. Antisperm Antibody Test
The antisperm antibody test is used to assess if antisperm antibodies are in blood, vaginal fluid, or semen, and assess the underlying cause of infertility.

Understanding the Antisperm Antibody Test
An immune system response can be caused by semen resulting in antibodies attaching to and killing sperm, causing immunologic infertility. These antibodies can be in blood, vaginal fluids, or semen. Antibodies can be made in a male if his sperm comes in contact with his immune system as a result of testicular injury, prostate gland infection, vasectomy, or other surgeries that expose sperm to the immune system. Semen in sperm can cause an allergic reaction in a female partner.
Some health care providers question the usefulness of the test since treatment is the same regardless of the test results.

3. Alpha-Fetoprotein (AFP) Test
The alpha-fetoprotein (AFP) test is used to assess:
- Fetal neural tube defects
- Spina bifida
- Anencephaly
- Edward’s syndrome (trisomy 18)
- Down’s syndrome (trisomy 21)
- Omphalocele
- Hepatoma in patients who have chronic hepatitis B or cirrhosis
- Lymphoma
- Hodgkin’s disease
- Renal cell cancer
- Ovarian cancer
- Testicular cancer
- Pancreatic cancer
- Effectiveness of cancer treatment

Understanding the Alpha-Fetoprotein Test
Alpha-fetoprotein is produced by the fetal liver and is detectable in a pregnant woman’s blood. The level of AFP rises gradually in the fourteenth week of gestation and continues rising until around the thirty-fourth week of gestation when the AFP level gradually decreases.
A high or low level of AFP is a sign that there may be a problem with fetal development. The AFP test is commonly administered as part of a maternal serum triple or quadruple screening test, which along with other factors including the pregnant woman’s age, is used to estimate the chance of birth defects.
The maternal serum triple screening test examines levels of:
- Alpha-fetoprotein
- Beta human chorionic gonadotropin (beta-hCG)
- Unconjugated estriol or uE3. (estrogen)
The maternal serum quadruple screening test examines levels of:
- The same substance as the maternal serum triple screening test
- The hormone inhibin A
A health care provider may also administer the AFP test in nonpregnant women and children and men to assess for a number of other diseases that cause a high level of AFP in the blood. These include lymphoma, Hodgkin’s disease, ovarian cancer, testicular cancer, renal cell cancer, and pancreatic cancer. Half of patients diagnosed with these cancers have normal AFP test results.

4. Follicle-Stimulating Hormone (FSH) Test
The follicle-stimulating hormone (FSH) test is used to assess the underlying cause of infertility and abnormal menstrual periods. It is also used to assess for precocious puberty, abnormal development of sexual organs, and the function of the pituitary gland.

Understanding the Follicle-Stimulating Hormone Test
The follicle-stimulating hormone is produced by the pituitary gland and controls sperm production by the testes and egg production in the ovaries. Follicle-stimulating hormone level is constant in men and changes with the menstrual cycle in women, with the highest level occurring during ovulation. The FSH test measures the level of the FSH in blood.
The health care provider may order the luteinizing hormone (LH) blood test, estrogen blood test, and the progesterone blood test in addition to the FSH test. The health care provider may order a sperm count or assessment of the patient’s ovarian reserve.

5. Human Chorionic Gonadotropin (hCG) Test
The human chorionic gonadotropin (hCG) test is used to assess for:
- Pregnancy
- Ectopic pregnancy
- Molar pregnancy
- Treatment for molar pregnancy
- Testicular cancer
- Choriocarcinoma

Understanding the Human Chorionic Gonadotropin Test
When a fertilized egg implants to the uterine wall, the placenta begins development. By the ninth day, the placenta produces the hCG hormone, which is detectable in the patient’s blood. The hCG test measures the level of hCG in blood. The level of hCG hormone is used as a sign of pregnancy, which is confirmed by other tests. In a normal pregnancy, the level of hCG hormone increases until 16. weeks’ gestation and then gradually decreases until birth when no hCG hormone is detectable. A lower level of hCG hormone might indicate an ectopic pregnancy and a higher level may indicate multiple fetuses. The hCG hormone test is typically ordered as part of a maternal serum screening test that is administered at 15. weeks’ gestation.
The hCG hormone can also be produced by a molar pregnancy, choriocarcinoma (uterine cancer), ovarian cancer, or other tumors. Testicular cancer also produces the hCG hormone in men. A normal hCG hormone level does not rule out cancer.
The level of hCG hormone can be detected before the patient misses her menstrual period and as early as 6. days after attachment of the egg. The hCG hormone test is also available as a urine test (home pregnancy test), which determines if the hCG hormone is present but does not measure the hormone’s level. The hCG hormone level is high 4. weeks following an abortion.

6. Inhibin A Test
The inhibin A test is used to assess the risk of Down’s syndrome and other birth defects.

Understanding the Inhibin A Test
Inhibin A hormone is secreted by the placenta and the level of the hormone is measured by the hormone inhibin A test. The hormone inhibin A test is a component of the quadruple screen test that is administered at the twentieth week of gestation to determine if there is a risk of birth defect in the fetus such as Down’s syndrome. The quad screen test also includes the AFP test, beta human chorionic gonadotropin (beta-hCG) test, and the uE3. test.
The hormone inhibin A test is not used to diagnose potential birth defects. Further testing is required if the hormone inhibin A test is abnormal.

7. Prolactin Test
The prolactin test is used to assess:
- Prolactinoma (pituitary gland tumor)
- Underlying cause of amenorrhea
- Underlying cause of infertility
- Underlying cause of nipple discharge
- Erectile dysfunction

Understanding the Prolactin Test
Prolactin is a hormone produced by the pituitary gland that increases during pregnancy, causing an increase in milk production and enlargement of the mammary glands. A high level of progesterone that occurs during pregnancy prevents milk from ejecting. Progesterone levels fall after delivery. As the newborn sucks the nipple to cause ejection of milk from the breast, this action simulates release of prolactin, causing lactogenesis and resulting in increased production of milk. Prolactin levels return to normal after delivery if the mother is not breast-feeding. The prolactin test measures the level of prolactin in the blood.

8. Phenylketonuria (PKU) Test
The phenylketonuria (PKU) test is used to assess for phenylketonuria.

Understanding the Phenylketonuria Test
Phenylalanine is an amino acid in breast milk, formula, dairy products, and meats. The body requires the phenylalanine hydroxylase enzyme to metabolize phenylalanine into tyrosine. Phenylketonuria is a genetic disorder in which the patient is missing the phenylalanine hydroxylase enzyme and is therefore unable to metabolize phenylalanine, causing a buildup of phenylalanine level in the blood that results in mental retardation and seizures. The PKU test measures the level of the phenylalanine hydroxylase enzyme in blood. The PKU test is administered to newborns between 12. and 28. hours after birth and again a week after birth.
Infants older than 6. weeks of age may be administered a PKU test if it was not performed at birth. Newborns who are ill are retested 3. weeks after birth.

9. Tay-Sachs Test
The Tay-Sachs test is used to assess for Tay-Sachs disease and if the patient is carrying the Tay-Sachs trait.

Understanding the Tay-Sachs Test
Hexosaminidase A is an enzyme that metabolizes ganglioside, which is a fatty acid. If hexosaminidase A is not present, ganglioside accumulates in brain and nerve cells, resulting in neural damage. This is referred to as Tay-Sachs disease, which is an inherited disease. The Tay-Sachs test measures the amount of hexosaminidase A in the blood.
A positive result will be confirmed by genetic testing.
The health care provider may order an amniocentesis or chorionic villus sampling of the placenta to determine if the fetus has the hexosaminidase A enzyme.

10. Sickle Cell Test
The sickle cell test is used to assess for sickle cell disease and if the patient is carrying the sickle cell trait.

Understanding the Sickle Cell Test
Normal red blood cells (RBCs) contain hemoglobin A. In sickle cell disease, RBCs contain hemoglobin S, which causes the RBC to form a sickle shape and is therefore called a sickled blood cell. Sickle cell disease is an auto-somal recessive disease in which the sickle cell gene must be inherited from both parents. Patients with sickled blood cells can experience a sickle cell crisis when sickled blood cells block blood vessels, resulting in decreased blood flow. Sickled blood cells are destroyed faster than normal RBCs, leading to sickle cell anemia. The sickle cell test determines if the patient has sickled blood cells.
The patient should undergo genetic counseling if the patient has the sickle cell trait or sickle cell disease.
The health care provider may order the high-performance liquid chromatography (HPLC) test to examine the patient’s DNA for the sickle cell gene. Sickle cell disease is more prevalent in African Americans. Health care providers commonly test newborns for the sickle cell trait, although infants <6. months old can have false-negative test results since they have fetal hemoglobin in their blood. The sickle cell test is therefore repeated after 6. months of age. The health care provider may order the sickle cell test for a fetus using chorionic villus sampling (CVS) or amniocentesis.

11. Hemochromatosis (HFE) Gene Test
The hemochromatosis (HFE) gene test is used to screen for the HFE gene and assesses the underlying cause and treatment of HFE.

Understanding the Hemochromatosis Gene Test
The hemochromatosis gene increases the absorption of iron (hemochromatosis), which causes a buildup of iron in the liver, heart, blood, joints, skin, and pancreas and results in joint pain, weight loss, and decreased energy. This can lead to arrhythmia, cirrhosis, diabetes, heart failure, arthritis, and change in skin color. The HFE gene test determines if the patient has the HFE gene.
Existence of the HFE gene means that the patient has an increased chance of having HFE, but does not mean that the patient has HFE. It is advised that the patient consult a genetic counselor before the test is administered to discuss the risks of developing HFE.
The health care provider will order the test if close family members have HFE. The health care provider might order the ferritin level test and transferring saturation test to measure the level of iron in the patient’s blood.

Basic Questions
Pregnancy and Genetic Tests

1. What is the purpose of the antisperm antibody test?
The antisperm antibody test is used to assess if antisperm antibodies are in blood, vaginal fluid, or semen, and to assess the underlying cause of infertility.

2. How might the immune system kill sperm?
An immune system response can be caused by semen resulting in antibodies attaching to and killing sperm, causing immunologic infertility.

3. Where are antisperm antibodies located?
These antibodies can be in blood, vaginal fluids, or semen.

4. How can antisperm antibodies be made?
Antibodies can be made in a male if his sperm comes in contact with his immune system as a result of testicular injury, prostate gland infection, vasectomy, or other surgeries that expose sperm to the immune system.

5. Why might the health care provider not order the antisperm antibodies test?
Some health care providers question the usefulness of the test since treatment is the same regardless of the test results.

6. What is the purpose of the alpha-fetoprotein (AFP) test?
The AFP test is used to assess for fetal neural tube defects, spinal bifida, anencephaly, Edward’s syndrome (trisomy 18), Down’s syndrome (trisomy 21), omphalocele, hepatoma in patients who have chronic hepatitis B or cirrhosis, lymphoma, Hodgkin’s disease, renal cell cancer, ovarian cancer, testicular cancer, pancreatic cancer, and effectiveness of cancer treatment.

7. Where is AFP produced?
AFP is produced by the fetal liver and is detectable in a pregnant woman’s blood.

8. What might a high or low AFP level indicate?
A high or low level of AFP is a sign that there may be a problem with fetal development.

9. Of what does the maternal serum triple screen test consist?
The maternal serum triple screening test examines levels of AFP, beta human chorionic gonadotropin (beta-hCG), and unconjugated estriol or uE3. (estrogen).

10. Why might a health care provider order the follicle-stimulating hormone (FSH) test?
The FSH test is used to assess the underlying cause of infertility and abnormal menstrual periods. It is also used to assess for precocious puberty, abnormal development of sexual organs, and to assess the function of the pituitary gland.

11. What is the function of FSH?
The FSH is produced by the pituitary gland and controls sperm production by the testes and egg production in the ovaries.

12. Is the FSH level normally constant?
The FSH level is constant in men and changes with the menstrual cycle in women, with the highest level occurring during ovulation.

13. What other test might a health care provider order along with the FSH test?
The health care provider may order the luteinizing hormone (LH) blood test, estrogen blood test, and the progesterone blood test in addition to the FSH test.

14. Why might the health care provider order the human chorionic gonadotropin (hCG) test?
The human chorionic gonadotropin (hCG) test is used to assess for pregnancy, ectopic and molar pregnancy, treatment for molar pregnancy, testicular cancer, and choriocarcinoma.

15. Why is the hCG test administered to determine pregnancy?
When a fertilized egg implants to the uterine wall, the placenta begins to develop. By the ninth day, the placenta produces hCG hormone, which is detectable in the patient’s blood.

16. Is the hCG test used to determine if the patient is pregnant?
No. Additional tests are necessary to confirm a pregnancy.

17. What might a low level of hGC indicate?
A low level of hCG hormone might indicate an ectopic pregnancy, and a high level might indicate multiple fetuses.

18. When is the peak period for hCG?
In a normal pregnancy, the level of the hCG hormone increases until 16. weeks’ gestation and then gradually decreases until birth when no hCG hormone is detectable.

19. What else besides pregnancy can produce hCG?
The hCG hormone can also be produced by a molar pregnancy, choriocarcinoma (uterine cancer), ovarian cancer, or other tumors.

20. Can hCG be produced in men?
Testicular cancer also produces the hCG hormone in men.

21. What is the purpose of the inhibin A test?
The inhibin A test is used to assess the risk of Down’s syndrome and other birth defects.

22. When is the inhibin A test administered?
The inhibin A hormone test is a component of the quad screen tests that is administered at the twentieth week of gestation.

23. Is the inhibit A test used to diagnose potential birth defects?
No. Further testing is necessary before a diagnosis is reached.

24. Why is the prolactin test ordered?
The prolactin test is used to assess for prolactinoma (pituitary gland tumor), the underlying cause of amenorrhea, infertility, and nipple discharge, and erectile dysfunction.

25. What is prolactin?
Prolactin is a hormone produced by the pituitary gland that increases during pregnancy, causing an increase in milk production and enlargement of the mammary glands.