91120:FRAGILE X DNA ANALYSIS

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91120:FRAGILE X DNA ANALYSIS
Alias Names: Frax A
Methodology: DNA Isolation
Edit Date: 11/8/2010
Performed: Monday
Released: 2 weeks after setup at PeaceHealth Laboratories’ reference lab.
CPT Code: 83890-905B / 83896-905B / 83898-905B / 83909-905B / 83912-905B
Specimen Collection Details
Collection: One 6 mL yellow top tube (ACD) Solution B, or one 8.5 yellow top tube (ACD) Solution A. Also acceptable: One 4 mL lavender top tube (EDTA).
Handling: Keep ambient. Do not centrifuge or separate.
Standard Volume: 5 mL whole blood.
Minimum Volume: 3 mL whole blood.
Transport: Ambient.
Comments: Testing is diagnostic for normal/carrier/disease states. Fragile X Syndrome is the most common hereditary cause of mental retardation. Testing is indicated in mentally retarded individuals and in individuals with a family history of mental retardation or learning disability of unknown etiology.
Rejection Criteria: Frozen specimen.
MEDICARE MAY REQUIRE A SIGNED ADVANCE BENEFICIARY NOTICE (ABN) FOR THIS TEST
This test may require insurance company prior authorization before ordering.
Please check the prior authorization list
.
Failure to gain preauthorization may result in denial of coverage.

Reference Range:
Measurement of CGG trinucleotide repeat number in exon 1 of the FMR-1 gene at Xq27.3.

Allele Types #CGG Repeats

Normal ~5 – ~44
Intermediate ~45 – ~54
Premutation ~55 – 200
Full mutation (disease-causing) >200
Interpretation
5-44 repeats No clinical phenotype
45-200 repeats No clinical phenotype but genetic counseling recommended.
>200 repeats Clinically affected males; females at risk for Fragile X syndrome.

PeaceHealth Laboratories