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Genetic test for detection of pathogenic variants in the DMPK gene (Myotonic Dystrophy Type 1)

Published: August 9, 2026Updated: August 16, 2026

This test checks for changes (mutations) in the DMPK gene, which may be linked to myotonic dystrophy type 1, a genetic condition affecting muscles and other body systems.

Quick summary

["This test helps determine if you may carry a genetic mutation associated with myotonic dystrophy type 1."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
21757-0
Short code
DMPK gene CTG Rpt Bld/T Ql
Synonyms
DMPK gene CTG Rpt Bld/T Ql
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
CPT
85610
SNOMED
396252006
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What This Test Measures

The test looks for specific variations (mutations) in the DMPK gene. These mutations can cause abnormal protein production, leading to myotonic dystrophy type 1 symptoms. The specimen used is whole blood, which contains DNA for analysis.

Why It Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of myotonic dystrophy type 1, a family history of the condition, or if you are considering genetic counseling or testing for relatives.

Sample Collection and Preparation

A blood sample is drawn from a vein in your arm. The blood is processed to extract DNA, which is then analyzed for mutations in the DMPK gene. This process is typically done in a laboratory setting.

What to Expect Before the Test

No special preparation is needed for this test. You may have some mild discomfort from the needle, but it usually goes away quickly. If you are pregnant or have a bleeding disorder, inform your healthcare provider before the test.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: whole-blood

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

DMPK Gene Mutation Test

Frequently asked questions

What does a positive result mean?
A positive result means you have been identified with mutations in the DMPK gene, which are associated with myotonic dystrophy type 1. This does not necessarily mean you will develop symptoms, as some people may be carriers without noticeable effects. Consult your healthcare provider for personalized interpretation and next steps.
What does a negative result mean?
A negative result means no mutations in the DMPK gene were detected in your sample. However, genetic testing can miss some mutations, so it is important to discuss the results with your healthcare provider. If you have symptoms or a family history, further testing or genetic counseling may still be recommended.
How long does it take to get results?
Results are typically available within 1 to 2 weeks after the sample is received by the laboratory. Your healthcare provider will contact you to discuss the results once they are ready.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy