What are other Names for this Test? (Equivalent Terms)
- CVS Test
What is Chorionic Villus Sampling Test? (Background Information)
- Chorionic villus sampling (CVS) is a technique that collects and analyzes cells from chorionic villi, late in the first trimester to test a developing fetus for genetic disorders
- Chorionic villi are finger-like projections that contain blood vessels of the growing baby. They are formed within the first 3 weeks of development. Chorionic villi are the first step towards the formation of a placenta
- As the villi enlarge, blood begins to flow through them and the heart of the embryo starts beating. This allows for transport of nutrients and waste products between the fetus and the mother
- Cells of the chorionic villus may be sampled and analyzed to determine the genetic makeup of the growing fetus. This can be done as early as the first trimester, or in the first 12-week period of pregnancy
- The Chorionic Villus Sampling Test screens a developing fetus for genetic disorders. The most frequently detected disorders using this test include trisomy 21 (Down’s syndrome), Klinefelter’s syndrome, Turner’s syndrome, and fragile-X syndrome
What are the Clinical Indications for performing the Chorionic Villus Sampling Test?
Following are the clinical indications for performing the Chorionic Villus Sampling Test:
- Screening for genetic disorders of a developing fetus
- Family history of trisomy 21 (Down’s syndrome), Klinefelter’s syndrome, Turner’s syndrome, and fragile-X syndrome
- Abnormal fetal development
- Pregnancy at a later age
How is the Specimen Collected for Chorionic Villus Sampling Test?
Following is the specimen collection process for Chorionic Villus Sampling Test:
Sample required: Chorionic villus cells
Process of obtaining a chorionic villus cell sample in adults:
- Through the cervix:
- A thin plastic tube is inserted into the vagina
- Using an ultrasound, the tube is guided through the vaginal canal and cervix to the placenta
- A sample of chorionic villus cells is obtained
- The tube is removed
- Through the abdomen:
- Using an ultrasound, a needle is inserted through the abdomen and guided through the uterus, into the placenta
- A syringe is used to draw a small amount of cells through the needle
- The needle is removed
Preparation required: No special preparation is needed prior to the test.
What is the Significance of the Chorionic Villus Sampling Test Result?
- A positive value for the Chorionic Villus Sampling Test may indicate a genetic disorder, such as trisomy 21 (Down’s syndrome), Klinefelter’s syndrome, Turner’s syndrome, and fragile-X syndrome
- In addition to the above, hundreds of other genetic disorders may be detected using the CVS Test
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
- The Chorionic Villus Sampling Test may be performed sooner in pregnancy than the amniocentesis test, which analyzes amniotic fluid. This is because there is no need for accumulation of large amounts of amniotic fluid for the test, which allows for it to be performed earlier
- The CVS Test carries a risk of miscarriage that is slightly higher than that posed by the amniocentesis test. However, it may be performed earlier in pregnancy, because there is no need for accumulation of large amounts of amniotic fluid for the Chorionic Villus Sampling Test
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.
What are some Useful Resources for Additional Information?
The following DoveMed website links are useful resources for additional information:
Please visit our Laboratory Procedures Center for more physician-approved health information:
References and Information Sources used for the Article:
Dugdale, D. C. (2011, June 18). Cerebral spinal fluid (CSF) collection. Retrieved from http://www.nlm.nih.gov/medlineplus/medlineplus.html
Kee, J. L. (2010). Laboratory and diagnostic tests with nursing implications (8th ed.). Upper Saddle River, NJ: Pearson.
Martini, F., Nath, J. L., & Bartholomew, E. F. (2012). Fundamentals of anatomy & physiology (9th ed.). San Francisco: Benjamin Cummings.
White, C. D. (2014, November 16). Chorionic villus sampling. Retrieved from https://www.nlm.nih.gov/medlineplus/medlineplus.html