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A genetic test checks the DNA of your cells. It can find changes in your genes, or it can check the number, order, and structure of your chromosomes. Testing may be done on samples of body tissue, blood, or other body fluids such as urine or saliva.
You inherit half of your genetic information from your mother and the other half from your father. Genes determine things such as your blood type, hair colour, and eye colour, as well as your risk for certain diseases. Testing can find gene or chromosome changes that may cause medical problems.
This test may be done to:
You do not need to do anything special to prepare for this test.
Talk with your doctor if you have any concerns about the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form .
The information found by a genetic test can have a huge impact on your life. So before you have the test, you may want to talk to a genetic counsellor or a doctor who specializes in genetics (geneticist). Genetic counselling can help you understand your genetic risks and decide if you want testing.
A genetic test can be done using almost any cell or tissue from the body.
For newborn testing, the blood sample is usually taken from the baby's heel instead of a vein. The health professional doing the heel stick will:
The health professional taking a sample of your blood will:
Cells are collected using amniocentesis or chorionic villus sampling.
To learn more, see:
Your baby may feel a little discomfort when the skin is pricked.
The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.
It is not painful to collect a saliva, urine, or semen sample.
There is very little chance of a problem from a heel stick. A small bruise may form at the site.
There is very little chance of a problem from having a blood sample taken from a vein.
Collecting a saliva, urine, or semen sample does not cause problems.
The information from a genetic test can affect you and your family in many ways. For example, it may have an impact on:
Genetic counselling is recommended before you have genetic testing. It can help you understand and make decisions about testing.
A genetic test checks the DNA of your cells. It can find changes in your genes, or it can check the number, order, and structure of your chromosomes.
The results of genetic testing depend on the type of test done. Genetic testing may be used to:
You may not be able to have the test, or the results may not be helpful, if you have a blood transfusion within a week before the test.
Other Works ConsultedFischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.Skirton H, Patch C (2009). Genetics for the Health Sciences: A Handbook for Clinical Healthcare, 2nd ed. Oxfordshire, UK: Scion Publishing.
Current as of: December 9, 2019
Author: Healthwise StaffMedical Review: Kathleen Romito MD - Family MedicineMartin J. Gabica MD - Family MedicineE. Gregory Thompson MD - Internal MedicineAdam Husney MD - Family MedicineElizabeth T. Russo MD - Internal MedicineSiobhan M. Dolan MD, MPH - Reproductive Genetics
Current as of: December 9, 2019
Author: Healthwise Staff
Medical Review:Kathleen Romito MD - Family Medicine & Martin J. Gabica MD - Family Medicine & E. Gregory Thompson MD - Internal Medicine & Adam Husney MD - Family Medicine & Elizabeth T. Russo MD - Internal Medicine & Siobhan M. Dolan MD, MPH - Reproductive Genetics
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