Ordering Recommendation

Use to diagnose myotonic dystrophy type 1 (DM1) in symptomatic individuals. May be used to screen for DM1 for adults with a family history. Specific allele sizing estimates cannot be determined for expanded alleles with greater than 150 CTG repeats.

New York DOH Approval Status

Testing is not New York state approved. Specimens from New York clients will be sent out to a New York state-approved laboratory.

Specimen Required

Patient Preparation
Collect

Lavender (K2EDTA), pink (K2EDTA), or yellow (ACD solution A or B)

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated. Also acceptable: Ambient.

Unacceptable Conditions
Remarks
Stability

Ambient: 1 week; Refrigerated: 1 month; Frozen: Unacceptable

Methodology

Polymerase Chain Reaction (PCR)/Capillary Electrophoresis

Performed

Varies

Reported

7-10 days

Reference Interval

By report

Interpretive Data

Refer to report


Phenotype
Number of CTG Repeats
Normal allele Less than or equal to 34
Premutation 35-49
Mild 50-approx. 150
Classic Approx.100-approx. 1000
Congenital >1000

Compliance Category

Laboratory Developed Test (LDT)

Note

Hotline History

N/A

CPT Codes

81234

Components

Component Test Code* Component Chart Name LOINC
3001908 Myotonic Dystrophy (DM1) - Specimen 31208-2
3001909 Myotonic Dystrophy (DM1) - Allele 1 35751-7
3001910 Myotonic Dystrophy (DM1) - Allele 2 35750-9
3001911 Myotonic Dystrophy (DM1) Interpretation 50398-7
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • DM1
  • DMPK
  • Myotonic dystrophy
  • Steinert disease
Myotonic Dystrophy Type 1 (DMPK) CTG Expansion