`E21.1` Secondary hyperparathyroidism, not elsewhere classified

Billable ICD-10-CM code, FY2026.

Excludes1 (never code together)

secondary hyperparathyroidism of renal origin (N25.81)

Applies from E21 Hyperparathyroidism and other disorders of parathyroid gland

Excludes1 (never code together)

adult osteomalacia (M83.-)
ectopic hyperparathyroidism (E34.2)
hungry bone syndrome (E83.81)
infantile and juvenile osteomalacia (E55.0)

Excludes2 (not included here)

familial hypocalciuric hypercalcemia (E83.52)

Risk adjustment (HCC)

CMS-HCC V22: HCC 23 — Other Significant Endocrine and Metabolic Disorders
RxHCC V08: HCC 43 — Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders
ESRD V24: HCC 23

MS-DRG index

Defines the logic of DRG(s) 643-645 in MDC 10.

Approximate ICD-9-CM (GEMs)

252.02 Secondary hyperparathyroidism, non-renal

Code annotations containing back-references to E21.1

Back-references to E21.1

Type 1 Excludes: E83.5 Disorders of calcium metabolism ("hyperparathyroidism (E21.0-E21.3)")
Type 1 Excludes: N25.81 Secondary hyperparathyroidism of renal origin ("secondary hyperparathyroidism, non-renal (E21.1)")

Back-references to E21

Type 1 Excludes: E83 Disorders of mineral metabolism ("parathyroid disorders (E20-E21)")
Code First: G63 Polyneuropathy in diseases classified elsewhere ("endocrine disease, except diabetes (E00-E07, E15-E16, E20-E34)")
Code First: M14.8 Arthropathies in other specified diseases classified elsewhere ("hyperparathyroidism (E21.-)")

Diagnosis Index entries for E21.1

Hyperparathyroidism › secondary (renal) › non-renal
Osteodystrophy › parathyroid, secondary

Nearby codes

E21 Hyperparathyroidism and other disorders of parathyroid gland
E21.0 Primary hyperparathyroidism
E21.1 Secondary hyperparathyroidism, not elsewhere classified (this code)
E21.2 Other hyperparathyroidism
E21.3 Hyperparathyroidism, unspecified
E21.4 Other specified disorders of parathyroid gland
E21.5 Disorder of parathyroid gland, unspecified