CPT® Code 81228

Cytogenomic (genome-wide) analysis for constitutional chromosomal abnormalities; interrogation of genomic regions for copy number variants, comparative genomic hybridization [CGH] microarray analysis

The CPT® Code 81228 refers to a specific type of molecular genetic testing known as cytogenomic analysis, which is utilized to identify constitutional chromosomal abnormalities. This analysis employs two primary techniques: bacterial artificial chromosome (BAC) microarray analysis and oligo-based comparative genomic hybridization (CGH). These methods are recognized as first-tier diagnostic tools for the postnatal evaluation of individuals who exhibit idiopathic mental retardation, developmental delays, autism spectrum disorders, and multiple congenital anomalies. In the BAC microarray analysis, a short segment of human DNA is amplified and integrated into a BAC, which facilitates the sequencing of the genome and the modeling of any genetic diseases present in the individual. The DNA samples for this analysis can be sourced from various biological materials, including products of conception such as umbilical cord and cord blood, as well as skin and peripheral blood samples. On the other hand, the oligo-based CGH technique involves labeling a test sample of human DNA and a reference DNA sample with distinct fluorophores. These samples are then hybridized to probes that are derived from known genes and non-coding regions of the genome, which are arranged on a glass slide. By measuring the fluorescence intensity ratio between the test DNA and the reference DNA, it becomes possible to assess copy number variations at specific genomic locations. The DNA for this method can be collected from primary cultured fibroblasts, saliva, and buccal swabs. Additionally, prenatal testing can be conducted on cells obtained through amniocentesis and chorionic villus sampling (CVS) when ultrasound or magnetic resonance imaging (MRI) indicates that a fetus may have congenital anomalies that pose a significant risk for unbalanced chromosome abnormalities, or when a balanced rearrangement has been detected through G-band analysis.