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Constitutional Chromosome Analysis, Blood Cytogenetics


TEST DIRECTORY
Test Name
Constitutional Chromosome Analysis, Blood Cytogenetics
Description
Chromosome analysis of blood is used for a wide variety of indications including mental retardation, failure to thrive, Down syndrome, delayed puberty, or primary amenorrhea (Turner syndrome), frequent miscarriages, infertility, multiple congenital anomalies, and sex determination.  Chromosome analysis is performed using standard cytogenetic techniques. When emergency cytogenetic evaluation of a critically malformed neonate is needed, a blood specimen for fluorescence in situ hybridization (FISH) may be submitted to rule out aneuploidy of sex chromosomes, and chromosomes 13, 18, and 21.
Test Code
22540
SPECIMEN REQUIREMENTS
Specimen
Blood
Specimen Requirements
Submit at least 3 mL of aseptically collected blood in a 5-mL sodium heparin (green topped) tube or 2-mL pediatric sodium heparin (green topped) tube.
DO NOT use lithium heparin tubes.
Supplies for Submission
Sodium heparin (green topped) tube
Specimen Collection
Send completed ProPath requisition form with the specimen.
Storage Requirements
Store specimens at room temperature (15 to 30°C) until transported. DO NOT freeze. Refrigerate if not transported immediately. Transport by courier at room temperature, adding a cold (refrigerator) pack during the summer months.
GENERAL AND TECHNICAL INFORMATION
Turn Around Time
4-10 days. Results are available overnight and may be available the same day for sex chromosomes and trisomy 18 if the specimen is submitted to the lab by 10:00 am. Routine chromosome analysis is also completed.
Methodology
Chromosome analysis is performed using standard cytogenetic techniques.
Limitations
A normal karyotype does not eliminate the possibility of birth defects such as those caused by submicroscopic cytogenetic abnormalities, molecular mutations, and environmental factors (i.e., teratogen exposure).
CPT Code
88230, 88262
To rule out mosaicism, add 88263.