FMR1 Gene Analysis Characterization of Alleles with Interpretation
Label Mnemonic: FX
Epic code: LAB2460
Order form: Molecular Genetics General Consult Requisition
Supply order: Supply Order Form
Billing: Billing Policies
CPT code: 81243 (PCR only)
81244 (PCR & Southern Blot)
Whole Blood
Collection Medium:
Pink top tube 6 mL (K2-EDTA)
Adult minimum: 3 mL whole blood in pink top tube (EDTA)
Children minimum: 2 mL whole blood in pink top tube (EDTA)
Testing on smaller volumes than those requested will be attempted.  
However, in some cases, small blood volumes may compromise the ability 
to perform testing.

Testing requires a dedicated collection tube.
Testing Schedule:
Turn Around Time:
21 days
Reference Range:
Normal: < or = to 44 CGG repeats
Indeterminate:  45-55 CGG repeats
Pre mutation (carrier):  56-199 CGG repeats
Full mutation (affected):  > or = to 200 CGG repeats
Send blood at room temperature.
Polymerase Chain Reaction (PCR) and Southern Blot
Sample Processing:
Do Not Centrifuge.
Label transport tube with two patient identifiers, date and time of collection.
Patient's age and sex is required on requisition for processing.
Relevant clinical information must be submitted with specimen in order to provide correct interpretation of test results.
Submit whole blood in original container.
Sample Storage:
Room temperature for up to 24 hours, then refrigerate the whole blood if it is necessary to be held overnight, weekends, or holidays.
Transport Instructions:
Recommend early AM overnight shipping or equivalent if not on courier service.
Place requisition into outside pocket of bag.
Ship refrigerated.
CPT Code:
81243 (PCR only)
81244 (PCR & Southern Blot)
See Additional Information:
Fragile X Syndrome Information