ICD-10 Code E20.812 – Autoimmune Hypoparathyroidism (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E20.812 – Autoimmune hypoparathyroidism
What it is
Autoimmune hypoparathyroidism is reduced parathyroid hormone production caused by an autoimmune process. The condition can lead to low calcium and related metabolic abnormalities.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include symptoms of hypocalcemia, such as muscle cramps, tingling, or tetany, along with evidence of parathyroid gland dysfunction.
When to use this code
Use E20.812 when the provider documents autoimmune hypoparathyroidism or clearly identifies an autoimmune cause of hypoparathyroidism. It is appropriate when the diagnosis is confirmed or treated as the active condition in the record.
Do not code from suspected autoimmune disease alone unless the documentation supports the diagnosis. Check documentation if the chart only states hypocalcemia, post-surgical hypoparathyroidism, or another non-autoimmune cause.
Do not use for
Do not use this code for hypoparathyroidism due to surgery, genetic disorders, or other specified causes. If the cause is not autoimmune, choose the more accurate documented diagnosis.
Coding tip
Code the documented etiology, not just low calcium; verify that the record explicitly supports an autoimmune cause.