Genetics• Updated 21 October 2026
Karyotype Test
A test that looks at the number and structure of a person's chromosomes.
Results: 2–3 weeks Specimen: Blood (or other tissue)
Quick Summary
Primary Purpose
To diagnose chromosomal conditions such as Down syndrome, and investigate recurrent miscarriage or infertility.
What It Measures
Chromosome number and structure.
Preparation
No preparation; genetic counselling is advised.
Overview
Karyotyping looks at all chromosomes under a microscope.
Smaller changes need other genetic tests.
What It Measures
Chromosomes
Count and arrangement.
How It's Performed
- 01
Sample
Blood from a vein.
- 02
Culture
Cells grown in the lab.
- 03
Analysis
Chromosomes examined.
Interpreting Results & Next Steps
Discuss with Doctor
Your doctor will explain what your result means and what happens next.
If values are High:
Abnormal results are explained by a genetic counsellor.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Karyotype Genetic Test(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Genetic and genomic testing(opens in a new tab) · NHS