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Colorado Genetics Labs

Standard Chromosome Analysis


Standard blood cytogenetic analyses detect abnormal chromosome number and major structural rearrangements: 

      • Trisomies
      • Monosomies
      • Larger partial deletions and duplications
      • Marker chromosomes
      • Other abnormalities, such as some translocations and inversions


High resolution chromosome analysis may be indicated if a more subtle cytogenetic change is suspected, such as interstitial deletions or duplications.  Follow-up FISH or chromosomal microarray (CMA) may be required to further characterize an abnormal finding.  


Indications for performing standard blood chromosome analysis include:

    • Developmental delay and/or multiple congenital anomalies suggestive of a particular trisomy
    • Abnormal size/growth and other features suggestive of a sex chromosome abnormality
    • Mental retardation
    • Ambiguous genitalia
    • Possible balanced translocation carrier
    • Recurrent miscarriages or infertility



A minimum of 20 metaphases are examined and 3 karyotypes are prepared at >450 band level.


Specimen Requirements
    • Submit 3 ml peripheral blood, cord blood, or cardiac blood in a 3 cc sodium heparin, green top tube
    • 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 Test Request Form​​, including pertinent clinical and family history.