ICD-10-CM 2027
ICD-10 code for hyponatremia
Confirmed by the official ICD-10-CM index entry “hyponatremia”. Page updated September 29, 2026.
About coding hyponatremia
The ICD-10-CM code for hyponatremia is E87.1 (Hypo-osmolality and hyponatremia).
It is also searched as low sodium.
Within E87 (other disorders of fluid, electrolyte and acid-base balance), E87.1 is specifically for Hypo-osmolality and hyponatremia. Related codes cover Hyperosmolality and hypernatremia (E87.0), acidosis (E87.2), Alkalosis (E87.3), mixed disorder of acid-base balance (E87.4), Hyperkalemia (E87.5), Hypokalemia (E87.6), fluid overload (E87.7) and other disorders of electrolyte and fluid balance, not elsewhere classified (E87.8).
Don't report E87.1 together with the conditions in its Excludes1 note: syndrome of inappropriate secretion of antidiuretic hormone (E22.2).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
Don't confuse with (Excludes1 for E87.1)
- syndrome of inappropriate secretion of antidiuretic hormone (E22.2)
Common questions about hyponatremia ICD-10 codes
What is the ICD-10 code for hyponatremia?
- E87.1 — Hypo-osmolality and hyponatremia.
Is E87.1 billable?
- Yes. E87.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E87.1 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E87.1 as a principal diagnosis.
Is E87.1 a CC or MCC?
- E87.1 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.