Lab Test

Chorionic Villus Karyotype

Chromosome Testing, Karyotyping, Chromosome Analysis, Karyogram, CVS, genetic, GCVGT, cytogenetics

Test Codes


Note: Current recommendations are that SNP chromosome microarray analysis should be considered prior to karyotype for any fetus with one or more ultrasound anomalies.



Specimen Collection Criteria

Collect: A minimum of 10 mg of chorionic villus tissue is collected either transcervically or transabdominally by a qualified Obstetrician.

  • Specimens are collected between 10 and 13 weeks gestation.
  • A copy of the requisition must be sent with the specimen.

Rejection Criteria

  • Specimens arriving in the Laboratory 4 days or more following the original collection date.
  • Specimens that are less than 10 mg are considered suboptimal and the Laboratory cannot guarantee a complete chromosome analysis.
  • Fixed or frozen tissue.

Inpatient Specimen Preparation

Specimen identification and quantity is determined by trained Cytogenetic Technologists that are present in Fetal Imaging at the time of specimen collection. The tissue is transported by the technologist to the Laboratory for immediate processing.

In-Lab Processing

Specimens are processed immediately upon receipt in the Laboratory.


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 96 hours
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days. A backup culture maintained for two weeks past sign-out of the final report.


Royal Oak Cytogenetics Laboratory


Monday – Friday, 8:00 am – 5:00 pm.
Results available within 10 days of receipt in the Laboratory.
STAT analysis must be arranged in advance with the Laboratory.

Reference Range

Normal results would be 46,XX or 46,XY with no apparent abnormalities present.

Test Methodology

High-resolution microscopic analysis of chromosomes to provide a digital image karyotype. Special stains or techniques such as C-Banding, NOR Banding, DAPI, Q-Banding and FISH may be required to further identify specific chromosomal abnormalities or variants.


Based on completion of chromosomal analysis. Interpretation will be issued in the form of a final report.

Clinical Utility

Karyotyping (chromosome analysis) is performed on prenatal specimens to determine the presence of chromosomal abnormalities. Karyotyping is most commonly performed on patients who are determined to be of advanced maternal age at the time of delivery (age 35 and above), when abnormalities are determined by ultrasound, or in the presence of an abnormal prenatal screen. The most common abnormalities associated with these increased risks are chromosomal aneuploidy syndromes (e.g., Down Syndrome-trisomy 21, Patau Syndrome-trisomy 13, Edward Syndrome-trisomy 18, Turner Syndrome-monosomy X), all of which can be identified by chromosomal analysis.

Clinical Disease

Abnormal karyotype results should be followed up with Genetic Counseling.

CPT Codes

88235, 88267, 88280, 88285.


Last Updated


Microtainer® and Vacutainer® are registered trademarks of Becton, Dickinson and Company.
UroVysion® is a registered trademark of Abbott Laboratories. ThinPrep® is a registered trademark of Hologic, Incorporated.