Karyotype Test

Karyotype is a test to determine and screen the shape, size and number of chromosomes in a sample of body cells. Excess, missing, or unusual positions of chromosome pieces can lead to problems with a person's growth, and body functions.

Why Karyotype Test Conducted

Karyotype is done to:

  • Ascertain if chromosomes of an individual have a disorder that can be inherited by his/her child.
  • Identify whether a chromosome disorder is preventing a woman from conceiving or causing miscarriages.
  • Analyze whether a chromosome abnormality is present in a fetus. Karyotyping also can be conducted to ascertain if chromosomal abnormalities may have affected the fetus to be stillborn.
  • Ascertain the reasons of a baby's disability or birth defects.
  • Enable determine the right treatment for a few types of cancer.
  • Identify the gender of an individual by ascertaining the presence of the Y chromosome. This may be done to identify newborn's sex.

How To Prepare

No particular preparation is required prior to this Karyotype test. Have a dialogue with your health care specialist about any concerns which you may have about the need for the test, its side effect, risks factor, and the process how it will be conducted.

How It Is Done

Karyotype testing can be conducted on any tissue or cell from the body. A karyotype test is generally conducted on a blood sample collected from a vein. For testing during pregnancy, it can be conducted on a sample of amniotic fluid or the placenta.

Blood Sample From a Vein

The health professional taking your blood will:

  • Wrap an elastic tube on your upper arm to cease the stream of blood. This enables the veins below the band bigger so that it is easier to push a needle into the vein as it becomes visible.
  • Clean the site of skin with alcohol.
  • Then the health care professional will push the needle into the vein. Multiple needle sticks may be required.
  • Attach a tube to collect the blood in it.
  • Detach the band from your arm after the blood collection process is over.
  • A gauze pad or cotton ball may be compressed over the needle site when the needle is removed.
  • Apply pressure to the site and then a bandage also.

Cell Sample From a Fetus

For this karyotyping test, cells are taken from the fetus facilitating amniocentesis or chorionic villu sampling.

Cell Sample From Bone Marrow

Bone marrow aspiration can also be facilitated for a karyotype test.

How It Feels

Blood Sample From a Vein

You may not experience anything at all from the needle puncture, or sometimes you may experience a short sting or pinch as the needle makes it way into the vein.

Risks

Blood Sample From a Vein

There is very little vulnerability of complications from having blood collected from a vein.

  • You may feel a small bruise at the site of puncture. You can alleviate the risk of bruising by compressing the site for several minutes post withdrawal of the needle.
  • In occasional cases, the vein may turn out to be inflamed after the blood sampling process. This condition, which is termed as phlebitis, is generally cured by a warm compress administered many times regularly.
  • Continued bleeding can be witnessed by people suffering with bleeding disorders. Blood-thinning drugs can also catapult the bleeding. If you have any such disorder, or if you are on blood-thinning drugs, tell your health professional prior to your blood is drawn.

Results

Karyotype is a test to ascertain and analyze the shape, size, quantity of chromosomes in a sample of body cells.

Reports of a karyotype test are available in 1 to 2 weeks in most of the cases.

Karyotype

Normal 

  • There are 46 chromosomes that can be considered as 22 matching pairs and 1 pair of sexchromosomes (XY for a male and XX for a female).
  • The shape, size, and quantity are normal for every chromosome.

Abnormal

  • If there are more than or less than 46 chromosomes.
  • If the shape or size of one or more chromosomes is unusual.
  • If a chromosome pair is broken or wrongly separated.

What Affects the Karyotyping Test

Causes you may not be able to undergo the test or the outcomes may not be useful include:

  • Being diagnosed or treated for cancer. Chromosomes may be eliminated or damaged by some stages of cancer treatment.
  • The site where the cells are taken.

Your doctor will talk with you pertaining to any reasons that can influence your test and the accuracy of the results.

What To Think About

  • Sometimes a karyotype test is blended with other genetic tests to offer more prominent information regarding genetic problems.
  • If the results of karyotype are not normal, other family members may also be recommended to go through the test.
  • Since the information acquired from karyotyping can influence your life, you may wish to consult a doctor specialist in genetics. These counselors are trained to assist you understand how karyotype test results are interpreted. A genetic counselor can enable you take well-informed decisions. Opt for genetic counseling prior to making a decision about a karyotype test.