___________________________, 20____
Attention: Preauthorization
Enrollee ID:
Group #:
Member:
Date of Birth:
To Whom It May Concern:
The purpose of this letter is to request coverage for medically necessary genetic testing for ______________________________,
DOB ____________________. ______________________ has the following clinical features:
Code:
Diagnosis:
_______
_________________________________________
_______
_________________________________________
_______
_________________________________________
These features suggest that _______________ may have a chromosomal abnormality that may not be detectable by traditional
chromosome analysis. A genetic diagnosis would assist us with _________________’s medical management and avoid the need to
pursue an additional and potentially costly diagnostic workup.
Microarray-based comparative genomic hybridization (array CGH) is available through the Clinical Genetics Laboratory at Michigan
State University. The CPT codes are circled below:
81229
Array CGH has the ability to test for a broad range of microscopic and submicroscopic chromosomal abnormalities through one test.
The advantages of this technology over existing ones (such as chromosome analysis and/or FISH), is that array CGH allows the
simultaneous detection of many conditions in a single test and may be cheaper than sequential testing with more traditional techniques
(which cost over $50,000 if ordered individually). Furthermore, the detection rate with array CGH is 4 to 5 times that of traditional
chromosome analysis.
A 2010 consensus statement published in the American Journal of Human Genetics recommends chromosomal microarray as firsttier clinical diagnostic test for individuals with developmental delay, autism/autism spectrum, cognitive impairment, dysmorphic
features, and/or congenital anomalies (Miller et al. 2010. Am J Med Genet. 86(5):749-64).
Additionally, chromosomal microarray has been shown to alter medical management in up to 54% of those tested and discovered to
have copy number variants (Coulter et al. 2011. 13(9):770-776).
As mentioned, chromosomal microarray is replacing routine chromosome analysis in many cases and provides significantly more
detailed information than karyotype alone. Published articles on the utility of microarray are too numerous to name; however, a few
additional pertinent reference articles are listed below:
 Copy-number variations associated with neuropsychiatric conditions. Cook EH Jr, Scherer SW. Nature. 2008.
455(7215):919-23.
 Novel submicroscopic chromosomal abnormalities detected in autism spectrum disorder. Christian S, et al. Biol
Psychiatry. 2008. 63(12):1111-7.
 Structural variation of chromosomes in autism spectrum disorder. Marshall CR, et al. Am J Hum Genet. 2008. 82(2):47788.
Enclosed is ________________’s most recent consult note with additional clinical information. If your analyst has any questions, we
request that he/she contact us before making a determination.
Thank you for your consideration of this request. We look forward to your decision.
Sincerely,