Skip to main content
Sign In

You have reached the Web site for the Department of Pathology at the University of Colorado Denver.

Colorado Genetics Labs
Colorado Genetics Laboratory

Chorionic Villi Sample Chromosome Analysis


Chorionic villi sample (CVS) chromosome analysis is performed to detect numerical and structural abnormalities such as:

    • Trisomies
    • Monosomies
    • Larger interstitial or terminal deletions and duplications
    • Translocations
    • Inversions
    • Mosaicism


Reasons to perform CVS chromosome analysis include:

    • Mother’s age 35 years or older at time of expected delivery
    • Prior pregnancy or child with a chromosomal abnormality
    • Abnormal ultrasound findings
    • Multiple miscarriages
    • Family history of a chromosomal abnormality
    • Mother of any age requesting prenatal testing
    • Abnormal non-invasive prenatal screen



A minimum of 20 metaphases are examined and 3 karyotypes are prepared from cultured preparations.

Trisomy Screen by FISH​ for common aneuploidies is performed in conjunction with the CVS chromosome analysis.


Specimen Requirements
    • Submit 20-30 mg chorionic villi in sterile, plastic screw-top tubes filled with transport media
    • Label specimen tube with patient’s name and a second identifier (ex: DOB, hospital ID)
    • Maintain specimen at room temperature and transport to the Colorado Genetics Laboratory immediately


Samples must be accompanied by a completed a Test Request Form, including pertinent clinical and family history, and  gestational age at the time of specimen collection.


Turn Around Time 

Generally 7-12 days, depending upon the viability and number of cells in the CVS sample. 


Trisomy Screen by FISH for Trisomy 21, 18 and 13, and sex chromosome aneuploidies is performed within 24-48 hours for quick analysis of the most common prenatal genetic conditions.