Chromosome Analysis — Peripheral Blood (Standard)

CPT Code(s): 88230, 88261, 88280, 88289

Service Code (IU Health): 53100293, 53100566, 53100715, 53100772

Ordering Recommendation: Detection of numerical and structural abnormalities of autosomes and sex chromosomes. G-banded karyotyping allows for the visualization and analysis of chromosomes for chromosomal rearrangements, including genomic gains and losses. Post-natal peripheral blood (leukocyte) chromosomes are indicated for an array of physical and/or mental difficulties. Approximately 7/1,000 live-births each year have a chromosome abnormality. Chromosomal microarray (CMA) is recommended if congenital anomalies are present that are not well defined by a known syndrome. CMA is also recommended for developmental delay and autism spectrum disorders. Companion fluorescence in-situ hybridization (FISH) testing may also be utilized.

Synonyms: Karyotype, G-bands, Constitutional, Congenital

Methodology: Tissue culture, high resolution microscopic analysis of G-banded chromosomes. If ordered, fluorescence in-situ hybridization (FISH) analysis of metaphase cells.

Performed: Monday through Saturday

Reported: 7-10 days

Patient Preparation: None

Collect: Whole blood in dark green-top sodium heparin tube.

Specimen Volume: Infants: 2-4 mL; Adults: 7-10 mL

Storage/Transport: Room temperature. Do not freeze or expose to extreme temperatures.

Unacceptable Conditions: Frozen or clotted specimens.

Remarks: Post-mortem, obtain by cardiac puncture within 1 hour. Physician notified if results are abnormal or if cultures result in no growth or contamination.   

Stability: Ambient: 48 hours; Refrigerated: 48 hours; Frozen: Unacceptable.

Characteristics:

Negative: A 46,XX or 46,XY karyotype indicating no apparent chromosomal abnormality is considered negative.

Positive: Identification of any numerical or structural chromosomal abnormality. A report detailing interpretation of results will be provided.

Limitations: This does not eliminate the possibility of low frequency mosaicism or small structural abnormalities. Living cells are required for chromosome analysis. As such, sample quality can affect the turnaround time. A normal karyotype, i.e. 46,XX or 46,XY with no apparent chromosome abnormality, does not eliminate the possibility that the birth defect may be caused by submicroscopic cytogenetic lesions, molecular mutations, and/or environmental factors such as exposure to teratogens.