E21.3 — Hyperparathyroidism, unspecified
E21.3 is a billable, specific ICD-10-CM code for hyperparathyroidism, unspecified. It is valid for submission on a claim.
Other codes that can never be billed with E21.3
These codes carry an Excludes1 note pointing at E21.3. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading E21.3 alone.
- E83.5Disorders of calcium metabolism
Risk adjustment
E21.3 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
E21.3 is named in 13 Medicare coverage policies — 13 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A56416Billing and Coding: Assays for Vitamins and Metabolic Function
- A56798Billing and Coding: Vitamin D Assay Testing
- A56841Billing and Coding: Vitamin D; 25 hydroxy, includes fraction(s), if performed
- A57122Billing and Coding: Parathormone (Parathyroid Hormone)
How E21.3 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 E21.3.
- Hyperparathyroidism
- Hyperfunction›parathyroid(gland)
- Arthritis, arthritic›in›hyperparathyroidism NEC
- Myopathy›in›hyperparathyroidism NEC
- Arthropathy›hemophilic NEC›in›hyperparathyroidism NEC
Related codes at this level
Codes that share E21. If E21.3 is not quite right, the correct code is usually one of these.
Questions about E21.3
- Is E21.3 a billable ICD-10-CM code?
- Yes. E21.3 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does E21.3 sit in the tabular list?
- Endocrine, nutritional and metabolic diseases (E00-E89), in the block Disorders of other endocrine glands (E20-E35).