Chromosome karyotype analysis (cytogenetics) Laboratory Test

Chromosome karyotype analysis is a lab test that looks at the number and structure of chromosomes in cells.

Chromosome karyotype analysis (cytogenetics) procedure illustration

Overview

Chromosome karyotype analysis is a lab test that looks at the number and structure of chromosomes in cells. After cells are grown and stained, the chromosomes are photographed and arranged in pairs to make a karyotype. This test can find extra or missing chromosomes and large changes such as deletions, duplications, translocations, and inversions. It is used in prenatal diagnosis, evaluation of developmental and birth differences, fertility workups, and to assess certain blood cancers.

Overview Preparation Clinical Info Recovery FAQ References

Also known as: Karyotype, Chromosome analysis, Cytogenetic karyotyping

Recovery
0–2 days
Return to Work
0–2 days

Preparation & Next Steps

Everything you need to know before and after your procedure

Before Care

  • Confirm the sample type for your test (blood, amniotic fluid, chorionic villi, or bone marrow) and where it will be collected
  • Most blood-based karyotypes do not require fasting; follow any specific instructions provided with your appointment
  • Bring a photo ID, insurance card, and the lab order or requisition if you were given one
  • Have an up-to-date list of medicines, supplements, and allergies available for intake forms
  • Plan extra time for consent and paperwork, especially for prenatal or bone marrow procedures
  • Arrange a ride if you are scheduled for an invasive prenatal procedure or bone marrow sampling
  • Verify insurance benefits and any needed preauthorization for genetic or cytogenetic testing
  • Set up patient portal access so you can receive results and messages about next steps

After Care

  • Keep the bandage on the blood draw site for several hours; mild soreness or a small bruise is common
  • Apply gentle pressure if minor oozing occurs and keep the area clean and dry
  • Follow clinic instructions after amniocentesis, CVS, or bone marrow sampling; plan light activity and rest as directed
  • Contact the clinic for fever, spreading redness, persistent bleeding, severe pain, fluid leakage, or new concerning symptoms
  • Note the expected timeline for results and how you will be notified
  • Use the patient portal or clinic phone to review results and ask clarifying questions
  • Keep a copy of the laboratory report in your personal health records
  • Genetic counseling is often available to help understand results that show chromosome changes

Clinical Information

Important medical details about this procedure

Indications

  • Prenatal diagnostic testing using amniocentesis or chorionic villus sampling
  • Abnormal prenatal screening or ultrasound findings
  • Unexplained infertility or recurrent pregnancy loss
  • Congenital anomalies, developmental delay, or growth concerns
  • Suspected sex chromosome differences
  • Evaluation of blood cancers (leukemia, lymphoma, myelodysplastic syndromes)
  • Family history of a known chromosomal rearrangement

Alternatives

  • Chromosomal microarray (CMA) to detect smaller gains and losses
  • Fluorescence in situ hybridization (FISH) for targeted rapid checks
  • Cell-free DNA screening (noninvasive prenatal screening) as a screening option, not diagnostic
  • Targeted gene testing or sequencing (exome or genome) for single-gene conditions
  • Quantitative or targeted PCR methods for common aneuploidies

Risks

  • From a blood draw: brief pain, bruising, lightheadedness, or rare infection
  • From amniocentesis or CVS: cramping, bleeding, infection, fluid leakage, and a small risk of pregnancy loss
  • From bone marrow sampling: pain at the site, bleeding, or infection

Contraindications

  • Active skin infection at the planned puncture site
  • Uncontrolled bleeding disorder or very low platelets for invasive sampling
  • Pregnancy-specific contraindications to amniocentesis or CVS are assessed by the obstetric team

Recovery Timeline

What to expect during your recovery

Most people have little to no recovery time after a standard blood draw. Invasive prenatal or bone marrow sampling may involve short rest and temporary soreness.

Typical Range

0–2 days

Return to Work

0–2 days

Recovery Milestones

Day 0

Resume routine light activities after a standard blood draw

Day 0–2

Tenderness or bruising at the draw site improves

Day 0–1

Light activity and rest after amniocentesis or CVS per clinic instructions

Day 7–21

Review results when available and confirm any follow-up testing plan

Frequently Asked Questions

Common questions and expert answers about this procedure

What does a karyotype show?

It shows the number and structure of your chromosomes, which can reveal extra or missing chromosomes and large structural changes.

How is the sample collected?

Common samples are blood for most people, amniotic fluid or chorionic villi during pregnancy, or bone marrow for certain blood cancers.

How long do results take?

Results often take 1 to 2 weeks because cells usually need to be grown in the lab before analysis.

Can a karyotype detect all genetic conditions?

No. It detects large chromosome changes. Small changes in DNA often need tests like chromosomal microarray or sequencing.

When is karyotyping used in pregnancy?

It is used for diagnostic testing after procedures like amniocentesis or CVS, especially when screening or ultrasound suggests a concern.

How is karyotyping used in cancer care?

In some blood cancers, it helps identify specific chromosome changes that aid diagnosis and guide treatment planning.

What if the lab cannot grow the cells?

Occasionally cultures fail. A repeat sample or a different genetic test may be requested.

How is a karyotype different from chromosomal microarray?

A karyotype sees large changes and whole extra or missing chromosomes. Microarray finds smaller gains and losses that a karyotype may miss.