ICD-10 Code E83.42 – Hypomagnesemia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E83.42 – Hypomagnesemia
What it is
Hypomagnesemia means the blood magnesium level is low. Use this code when documentation identifies magnesium deficiency as the diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Commonly noted findings may include neuromuscular irritability, weakness, tremor, or cardiac rhythm concerns when magnesium deficiency is clinically significant.
When to use this code
Use E83.42 when the provider documents hypomagnesemia, magnesium depletion, or low magnesium as an active diagnosis. It also fits when the condition is the reason for evaluation, monitoring, or follow-up. If the record only shows an abnormal lab without diagnosis, check documentation.
Do not use for
Do not use this code for normal magnesium results or for nonspecific electrolyte abnormalities without documented hypomagnesemia. Check documentation if the low value is only incidental or not confirmed by the provider.
Coding tip
Assign E83.42 only when the provider clearly links the low magnesium finding to a diagnosis.