ICD-10 Code E22.2 – Syndrome of inappropriate secretion of antidiuretic hormone (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E22.2 – Syndrome of inappropriate secretion of antidiuretic hormone
What it is
This code identifies syndrome of inappropriate secretion of antidiuretic hormone, a disorder where the body retains too much water because antidiuretic hormone is released or acts inappropriately. It is used when the diagnosis is documented.
Clinical signs
Common findings include hyponatremia with low serum osmolality and inappropriately concentrated urine. Patients may have nausea, confusion, headache, or other neurologic changes; clinical features vary, so refer to documentation.
When to use this code
Use E22.2 when the provider documents SIADH, inappropriate antidiuretic hormone secretion, or a clearly equivalent diagnosis. Code it for confirmed cases during inpatient or outpatient encounters when the condition is part of the assessment or active management. If the record only notes hyponatremia without SIADH, do not assume this code.
Do not use for
Do not use this code for nonspecific low sodium, dehydration, or other causes of hyponatremia without documentation of SIADH. Check documentation if the etiology is unclear.
Coding tip
Assign E22.2 only when SIADH is explicitly documented; if the cause of hyponatremia is uncertain, query the provider.