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High Resolution Chromosome Analysis


High resolution chromosome analysis detects:

    • Interstitial microdeletions and microduplications greater than 4.0 Mb in size 
    • Subtle balanced rearrangements
    • Partial trisomies
    • Partial monosomies
    • Marker chromosomes
    • Translocations
    • Inversions  

Follow-up studies, such as chromosomal microarray (CMA) or fluorescence in situ hybridization (FISH), may be recommended if a more subtle chromosomal abnormality is suspected. 

Indications for performing high resolution chromosome analysis include:

    •  Developmental delays
    • Growth delay
    • Intellectual disability
    •  Multiple congenital anomalies
    • Abnormal phenotype that is not consistent with a particular trisomy or sex chromosome abnormality
    • Positive family history for abnormal pregnancy outcome
    • Recurrent miscarriage or infertility
    •  Phenotype suggestive of a particular microdeletion or microduplication syndrome                     


A minimum of 20 metaphases are examined, with emphasis on specific chromosome sub-band regions at ≥650 band stage of chromosome condensation, and 3 karyotypes are prepared.

Molecular cytogenetic studies using fluorescence in situ hybridization (FISH) are often performed in addition to high resolution studies when a microdeletion syndrome is suspected.


Specimen Requirements 
  • Submit 3 ml peripheral blood specimen 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.