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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.