Karyotype / Chromosome Analysis

Referral required: This genetic test can only be booked with a referral from your GP or specialist. Results are returned to your referring clinician.

Chromosome analysis, also known as karyotyping, examines the number and structure of the chromosomes in your cells. Chromosomes carry your genetic material (DNA), and most people have 46, arranged in 23 pairs. This test produces an organised picture of your chromosomes, allowing specialists to check for missing, extra, or structurally altered chromosomes that can be associated with certain genetic conditions.

What it is used for

• Investigating genetic conditions: karyotyping can identify chromosomal disorders such as Down syndrome (an extra chromosome 21), Turner syndrome, Klinefelter syndrome, and others
• Investigating fertility and recurrent pregnancy loss: chromosomal changes in a parent can be a cause of infertility or repeated miscarriage
• Assessing developmental or growth concerns: as part of a wider specialist investigation
• Family investigation: where a chromosomal change has been identified in a relative

Understanding the results

The result describes the number and structure of your chromosomes. A normal result shows the expected 46 chromosomes with no visible structural changes. An abnormal result may show an extra or missing chromosome, or a structural change such as a rearrangement, which is then interpreted in the context of the reason for testing.

An important note on interpretation

Karyotyping is a specialist test, and its findings require expert interpretation. It detects changes at the level of whole or large parts of chromosomes, but it does not detect smaller genetic changes within individual genes, which need different tests. Some findings are clearly significant, while others are of uncertain or no clinical importance. Your referring clinician will interpret your result in the context of the reason for testing and your clinical history, and where appropriate, genetic counselling can help explain what a result means for you and your family.

Why it matters

Chromosome analysis can provide important answers in the investigation of genetic conditions, fertility problems, recurrent miscarriage, and developmental concerns. Because it is a specialist test with results that require expert interpretation and can have implications for the wider family, it is carried out on referral so that your results are understood and applied appropriately within your care.

• Chromosome analysis (karyotype)

No special preparation required.

For blood tests, we recommend drinking plenty of water beforehand to ensure smooth sample collection. If you are taking any regular medication, continue to do so unless advised otherwise by your doctor.