What are the other Names for this Test? (Equivalent Terms)
- Fetal Blood Sampling Test
- PUBS Test
- Umbilical Vein Sampling Test
What is Cordocentesis? (Background Information)
- Cordocentesis is a method of obtaining blood from a fetus, for further analysis. The blood is obtained using a fine needle guided by ultrasound to the umbilical cord, which connects a mother to her infant
- The umbilical cord contains a vein and two arteries that provide the fetus with blood and carry away wastes. Sampling of this blood, yields information about the fetus that can be used to assess various aspects of its health. These include genetic abnormalities, blood disorders, and infections
- An ultrasound is performed to locate the umbilical cord. An ultrasound is a noninvasive procedure in which a small transducer is pressed against a mother’s skin, or inserted into her vagina. High-frequency waves (ultrasounds) are created that deflect from the fetus and umbilical cord, giving their position on a monitor
- A Cordocentesis can then be performed. It is also termed as Percutaneous Umbilical Cord Blood Sampling (PUBS) Test
- A Cordocentesis is a blood test used to obtain fetal blood for analysis. A needle is inserted into the abdomen to reach the umbilical cord and a small amount of blood is acquired for analysis. Alternatively, using this technique, medicines may also be administered to the infant
What are the Clinical Indications for performing the Cordocentesis Test?
Following are the clinical indications for performing Cordocentesis:
- Testing for genetic abnormalities, such as Down’s syndrome
- Testing for infection, blood disorders
- Testing for isoimmunization, which occurs when the mother forms an immune response against her fetus
- In order to provide therapy to a fetus
A Cordocentesis is more prone to complication than tests, such as an amniocentesis or a chorionic villus sampling. Consequently, it is reserved only for cases, where more information is required, than these tests can provide.
How is the Specimen Collected for Cordocentesis Test?
Following is the specimen collection process for a Cordocentesis test:
Sample required: Blood
Process: Insertion of a needle into a mother’s abdomen, to reach the umbilical cord
Preparation required: No special preparation is needed prior to the test. However, Cordocentesis can be performed only during weeks 18-22 of pregnancy.
What is the Significance of the Cordocentesis Test Result?
Abnormalities detected through a Cordocentesis test may indicate:
- Fetal infection
- Fetal platelet count in the mother
- Fetal anemia
- Fetal malformation
- Fetal genetic defects, such as Down’s syndrome
- Isoimmunization (production of antibodies against red blood cells)
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:
Cordocenteses are not without certain risks:
- In 1-2% of cases, Cordocentesis results in a miscarriage
- Side effects from the procedure could include infection, drop in infant heart rate, premature rupture of membranes (“breaking the water”), fever, and chills
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, 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.
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References and Information Sources used for the Article:
American Pregnancy Association. (2006, February). Cordocentesis: Percutaneous Umbilical Blood Sampling (PUBS).
Lab Tests Online (2013, November 18). Retrieved June 30, 2014 from http://labtestsonline.org/understanding/ wellness/pregnancy/second-trimester/cordo/
Martini, F., Nath, J. L., & Bartholomew, E. F. (2012). Fundamentals of anatomy & physiology (9th ed.). San Francisco: Benjamin Cummings.
Schnell, Z. B., Van, L. A., & Kranpitz, T. R. (2003). Davis's Comprehensive handbook of laboratory and diagnostic tests: With nursing implications. Philadelphia: F.A. Davis.