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FISH for Chromosome 21

FISH for Chromosome 21

Fluorescence In Situ Hybridization, commonly known as FISH, is a sophisticated laboratory technique utilized to detect specific DNA sequences on chromosomes. FISH for chromosome 21 is primarily employed in prenatal diagnosis to ascertain chromosomal abnormalities, most notably Down syndrome, which is also referred to as Trisomy 21.

Understanding if an unborn child has a chromosomal abnormality is critical as it facilitates early intervention, well-informed decisions regarding the pregnancy, and preparation for the child's health and development needs.


  • Test NameFISH for Chromosome 21
  • Sample TypeBlood
  • Preparations RequiredThere are no specific patient preparations required for blood samples. For amniotic fluid samples, it is essential to follow the doctor's instructions regarding prenatal testing.
  • Report Time5 days

What is FISH for Chromosome 21?

FISH for Chromosome 21 is a genetic test that employs fluorescent probes to identify and map the genetic material in a person's cells, focusing on chromosome 21. It is especially useful in detecting Down syndrome, which is associated with an extra copy of chromosome 21.

Why is FISH for Chromosome 21 significant?

This test is vital for early detection of Down syndrome and other chromosome 21 anomalies. Identifying these conditions before birth can help in making informed decisions regarding the pregnancy and preparing for the care that the child may require.

Home Sample Collection Process

1
Book your convenient slot
Book your convenient slot
2
Sample Collection by Phlebotomist
Sample Collection by Phlebotomist
3
Reporting of the sample at lab
Reporting of the sample at lab
4
Download Reports
Download Reports
Frequently Asked Questions

It is often recommended during pregnancy, especially if there is an increased risk of chromosomal abnormalities due to factors like advanced maternal age, family history, or abnormal results from other screening tests.

For prenatal testing, the sample is usually taken from the amniotic fluid through amniocentesis. For other types of testing, a blood sample is collected.

Down syndrome, or Trisomy 21, occurs when there is an extra copy of chromosome 21. It is characterized by intellectual disabilities, distinctive facial features, and potentially other health issues like heart defects.

Besides Down syndrome, there are other, rarer abnormalities associated with chromosome 21, such as Robertsonian translocations and mosaic Down syndrome.

If an extra copy of chromosome 21 is detected, it usually indicates Down syndrome. It is essential to discuss the results and implications with a genetic counselor or a doctor specializing in maternal-fetal medicine.

FISH can reliably detect the number of copies of chromosome 21 but does not provide information on structural abnormalities or mutations within the chromosome.

Amniocentesis carries a small risk of miscarriage, infection, or injury to the fetus. It is important to have a detailed discussion with the doctor regarding the risks and benefits of amniocentesis.

If the test indicates Down syndrome, it is essential to consult a doctor or genetic counselor to understand the condition and discuss the available options and resources for care and support.

The primary limitation of the FISH test is that it only detects the number of copies of chromosome 21 and does not provide detailed information on the structure or specific mutations.

FISH is highly accurate for counting the number of chromosomes. However, it should be complemented with other tests for a comprehensive understanding of genetic health.

Technical issues with the sample or mosaicism (where some cells have a different chromosomal makeup) can affect the results.

If abnormalities are detected, additional genetic testing, consultations with genetic counselors, and a detailed fetal assessment may be recommended.

Consulting a geneticist or a maternal-fetal medicine specialist is advisable for proper interpretation and guidance regarding the test results.

FISH for Chromosome 21 is an invaluable tool that provides crucial insights into the genetic health of an unborn child, particularly in the context of Down syndrome. Early detection of chromosomal abnormalities empowers expecting parents and healthcare professionals to make well-informed decisions. It is essential to engage in discussions with specialists to fully comprehend the implications of the test results and understand the range of options and support available.

FISH for CHROMOSOME 21
₹ 3800
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Locations Near You in Hyderabad
  • 4KM from Madhapur
  • 3KM from Banjara Hills
  • 1.9KM from Yusufguda
  • 3KM from Madhura Nagar
  • 5KM from Shaikpet