The karyotype test is a blood or body fluid test that analyses your chromosomes. The parts of cells that have genes are called chromosomes. Your parents will pass on these genes to you. Your genes determine your genetic traits, such as your eye colour and skin colour.
The average person has 23 pairs of chromosomes (46 total). Half of your chromosomes come from your mother, and the other half is from your father.
Sometimes, people have extra chromosomes, or there are missing chromosomes. Sometimes, chromosomes may be of unusual size, shape, or order. You might have a genetic disorder or disease if you have unusual chromosomes in your body.
Who needs the karyotyping test?
This type of genetic testing may be required for adults if:
- They are having difficulty getting pregnant or trying to get their partner pregnant. Sometimes, infertility can be caused by a genetic disorder.
- Certain cancers and blood disorders. Multiple myeloma, leukaemia, and lymphoma are all possible diseases that can alter your chromosomes. These abnormalities can be identified using karyotyping. This will help you to plan your treatment.
- You have a family history of certain genetic disorders. An analysis of your chromosomes can reveal if you have any abnormal chromosomes or what the likelihood is that they will be passed to your children.
- If unborn babies are at risk for genetic disorders, they may require karyotyping.
- Mothers over 35 years old when they become pregnant.
- Children of parents with genetic disorders.
- A karyotype test is used to determine if a genetic disorder caused the death of a baby who died late in pregnancy or during birth.
- If a child has a genetic disorder, a chromosome test may be required. There are many genetic conditions, each with its own symptoms. So, a test is important to decide on the next step.
How is this test performed?
Different healthcare providers take different testing approaches. They take fluid or blood samples, depending on what karyotype test is required. Geneticists trained in chromosome analysis analyse the fluid or blood in a laboratory.
How to prepare for this test?
A majority of people don’t have to do anything in preparation for a karyotyping exam. However, you should consult your healthcare provider if there have been any recent blood transfusions.
Sometimes, your healthcare provider may ask you to fast (not eat and drink) before your test. Ask your provider about any special instructions or medication caution you need to follow before the test.
Before having a Karyotyping Test, some people prefer to consult a genetic counsellor. A test can have profound emotional consequences. Parents who discover their child has a genetic disorder may especially feel bad. So, whether to take or not take this test is entirely your decision. It’s up to you to consider what the benefits and risks are before you make a decision.
Types of karyotyping testing—
The most commonly used method to test for chromosomes in children, infants, and adults is blood testing.
Bone aspiration, or biopsy, is a procedure that tests bone marrow for certain cancers and blood disorders.
Amniocentesis is the procedure that takes a sample from the amniotic fluid, the protective fluid around a baby in the womb.
The CVS (chorionic villus sampling) takes a sample from the placenta. The placenta develops in the womb during pregnancy and provides oxygen and nutrients to the foetus.
Risks involved in the test—
A blood test is not associated with any significant risk. However, you may experience the following:
- There might be light bleeding from the point where the needle entered your vein.
- You might feel soreness in your armpits.
Bone marrow biopsy and aspiration—
There are several risks associated with a bone marrow biopsy and aspiration.
- The injection site may feel sore or painful.
- Feeling tingling in your legs.
Here are the risks of CVS or amniocentesis—
- Infection of the uterus.
- Miscarriage: About 1 out 100 women experiences a miscarriage following CVS. Less than 1 in 200 miscarry after amniocentesis.
- Virus transmission is uncommon. However, if your blood contains a virus that mixes with the baby’s during the procedure, the virus could be transmitted to them.
How long does it take to get the results?
The results of your karyotype tests may take a few weeks to come. However, it can take a longer or shorter duration. Talk to your healthcare provider about when your results can be expected.
What do positive test results indicate?
An abnormal karyotype test result could indicate that you or your baby has unusual chromosomes. This could indicate genetic disorders and diseases such as:
- Trisomy 21, which is also known as Down syndrome, which can cause intellectual disabilities and developmental delays.
- Trisomy 18, also known as Edwards syndrome, is a severe condition that causes serious problems in the heart, kidneys, and lungs.
- Patau syndrome is a condition that causes low birth weight and poor development in the womb.
- Turner syndrome is a condition that prevents women and girls from developing feminine characteristics.
The karyotype test is used to check blood and body fluids for abnormal chromosomes. To detect genetic conditions, this test may be required for children and adults as well as babies in the womb. Talk to your healthcare provider about genetic counselling before you decide to get karyotype testing. Counselling can help you to weigh the benefits and risks of chromosome analysis.