Karyotyping Test

Karyotyping is carried out to:

• To determine whether an adult's chromosomes contain an alteration that might be passed on to a child.
• See if a chromosome defect prevents a woman from getting pregnant or if it causes miscarriages.
• Check to see if a fetus has a chromosomal defect.
• Karyotyping can also determine whether chromosomal issues led to the fetus's stillbirth.
• Find the cause of any congenital disabilities or disabilities in a newborn.
• Assist in determining the best course of treatment for certain cancers.

A karyotype test evaluates the shape, size, and number of chromosomes, which are parts of the cells containing genes. Genes are parts of DNA passed down from one's mother and father. It is usually performed to detect genetic abnormalities that a developing baby has.

Karyotyping test requires a blood sample. A tourniquet (elastic) band is placed tightly on the upper arm. The patient is then asked to make a fist. This helps in the build-up of blood filling the veins. The skin is disinfected before needle insertion and the blood sample is collected in vacutainer.

Adults may need Karyotyping testing if they:

• Have issues getting pregnant or their partner pregnant. Occasionally infertility in men or women can be caused by a genetic defect.
• Have certain blood disorders or cancers. Chromosome changes can occur due to illnesses, including multiple myeloma, lymphoma, leukaemia, or anaemia. Karyotyping can detect these anomalies and help with treatment.
• Have a family history of particular genetic illnesses. Chromosome analysis can reveal whether one has abnormal chromosomes and how likely it is to be passed on to offspring.

Complete Process

• Karyotype testing can be performed using almost any tissue or cell from the body. 
• A blood sample drawn from a vein is typically used for a karyotype test.

Blood sample from a vein

The healthcare worker taking the blood will:

i. Tie an elastic band across the upper arm to prevent blood flow. This enlarges the veins underneath the band, making it easier to insert a needle.

ii. Use alcohol to clean the needle site.

iii. Insert the needle into the vein. They might use more than one needle.

 iv. Affix a tube to the needle to fill it with blood.

v. Untie the band from the arm when enough blood has been collected.

vi. Place a cotton ball or gauze pad above the needle site once the needle is removed.

vii. Bandage the area after applying pressure to the site.

• A placenta or amniotic fluid sample could be used for testing during pregnancy. Cells from the fetus are extracted utilising chorionic villus sampling or amniocentesis.
• In addition, a Karyotype Test may be performed via a bone marrow aspiration.

Precautions to Be Taken

There is no particular preparation needed for this test. One can get advice from a genetic counsellor or a specialist doctor to make sound decisions. Before choosing to get a genetic test, request genetic counselling.

After The Test

A blood test carries no substantial risks, although one could experience the following:

• Light bleeding at the site of the vein puncture.
• Soreness inside the arms.

Abnormal karyotype test results could indicate that the parent or the child has atypical chromosomes. This could be an indication of genetic illnesses and disorders, like:

• Edwards syndrome, also referred to as trisomy 18, results in severe problems with the heart, kidneys, and lungs.
• Down syndrome, trisomy 21, results in intellectual disabilities and developmental delays.
• Turner syndrome inhibits female traits from developing in girls and women.
• Patau syndrome results in low birth weight and poor development in the womb.