Standard blood cytogenetic analyses detect abnormal chromosome number and major structural rearrangements:
- 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 2 karyotypes are prepared at >450 band level.
- 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.