Is E21.5 a billable ICD-10-CM code?

Yes. E21.5 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does E21.5 sit in the tabular list?

Endocrine, nutritional and metabolic diseases (E00-E89), in the block Disorders of other endocrine glands (E20-E35).

What cannot be coded together with E21.5?

E21.5 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above E21.5 (E21) and apply to it just the same.

E21.5

E21.5 — Disorder of parathyroid gland, unspecified

Billable / specific codeICD-10-CM

E21.5 is a billable, specific ICD-10-CM code for disorder of parathyroid gland, unspecified. It is valid for submission on a claim.

Excludes1 inherited from the categories above E21.5

These are not written on E21.5, but they bind it: a note on a category applies to every code beneath it. Billing E21.5 with anything listed here is a denial.

Written on E21 — Hyperparathyroidism and other disorders of parathyroid gland

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

Excludes2 inherited from the categories above E21.5

Also inherited, and the opposite of Excludes1: these conditions are not part of E21.5, but a patient can have both, so you may code both.

Written on E21 — Hyperparathyroidism and other disorders of parathyroid gland

familial hypocalciuric hypercalcemia (E83.52)

Risk adjustment

E21.5 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

E21.5 is named in 3 Medicare coverage policies — 3 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

A57361Billing and Coding: Monitored Anesthesia Care
A57484Billing and Coding: Vitamin D Assay Testing
A57484Billing and Coding: Vitamin D Assay Testing

How E21.5 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to E21.5.

Disease, diseased›parathyroid(gland)
Disorder›parathyroid(gland)

Code history

E21.5 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share E21. If E21.5 is not quite right, the correct code is usually one of these.

Questions about E21.5

Is E21.5 a billable ICD-10-CM code?: Yes. E21.5 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does E21.5 sit in the tabular list?: Endocrine, nutritional and metabolic diseases (E00-E89), in the block Disorders of other endocrine glands (E20-E35).
What cannot be coded together with E21.5?: E21.5 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above E21.5 (E21) and apply to it just the same.