ICD-10 Code E74.04 – McArdle disease (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E74.04 – McArdle disease
What it is
E74.04 identifies McArdle disease, a glycogen storage disorder that affects how muscle uses stored glycogen for energy. Code it when documentation names McArdle disease or glycogen storage disease type V.
Clinical signs
Typical findings include exercise intolerance, early muscle fatigue, cramps, and episodes of muscle pain or weakness during activity. Some patients report dark urine after exertion; clinical features vary, so refer to documentation.
When to use this code
Use E74.04 when the provider documents McArdle disease, glycogen storage disease type V, or a confirmed diagnosis of muscle phosphorylase deficiency. You may also use it when the record clearly links the patient’s symptoms to this inherited disorder.
Do not assign it for nonspecific muscle pain, routine exercise fatigue, or an unconfirmed metabolic myopathy. If the chart only says “possible” or “rule out,” check documentation before coding.
Do not use for
Do not use this code for other glycogen storage diseases, general metabolic disorders, or isolated rhabdomyolysis without McArdle disease documented. Check documentation when the diagnosis is uncertain.
Coding tip
Look for the exact disease name or type V wording in the assessment, problem list, or discharge summary before assigning E74.04.