ICD-10-CM 2027 diagnosis code
E21.2Other hyperparathyroidism
E21.2 is a valid, billable ICD-10-CM code for other hyperparathyroidism. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About E21.2
E21.2 is the ICD-10-CM diagnosis code for other hyperparathyroidism. It belongs to category E21 (hyperparathyroidism and other disorders of parathyroid gland), block E20-E35 (disorders of other endocrine glands) and chapter 4 (endocrine, nutritional and metabolic diseases). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within E21, choose E21.2 (Other hyperparathyroidism) only when documentation doesn't support a more specific option: primary hyperparathyroidism (E21.0), secondary hyperparathyroidism, not elsewhere classified (E21.1), hyperparathyroidism, unspecified (E21.3), other specified disorders of parathyroid gland (E21.4) and disorder of parathyroid gland, unspecified (E21.5).
The conditions in its Excludes2 note aren't part of E21.2, but may be coded alongside it if the patient has both: familial hypocalciuric hypercalcemia (E83.52).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 643 (Endocrine Disorders with MCC, relative weight 1.6139), DRG 644 (Endocrine Disorders with CC, relative weight 1.0044) and DRG 645 (Endocrine Disorders without CC/MCC, relative weight 0.7459), in MDC 10 (Endocrine, Nutritional and Metabolic Diseases and Disorders), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as 252.08 (other hyperparathyroidism).
Coding notes
- Tertiary hyperparathyroidism
- familial hypocalciuric hypercalcemia (E83.52)
Notes that apply from higher levels
Instructions written at a parent level also apply to E21.2.
Broader instructions also apply from E20-E35 Disorders of other endocrine glands and Chapter 4: Endocrine, nutritional and metabolic diseases.
Alphabetic index entries
2 entriesTerms in the official ICD-10-CM index that lead to E21.2.
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 10 · Endocrine, Nutritional and Metabolic Diseases and Disorders
ICD-9-CM equivalent
Converter →- 252.08Other hyperparathyroidismexact
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about E21.2
Is E21.2 billable?
- Yes. E21.2 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E21.2 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E21.2 as a principal diagnosis.
Is E21.2 a CC or MCC?
- No. E21.2 is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does E21.2 group to?
- E21.2 is used in the MS-DRG v44.0 logic for MS-DRG 643 (Endocrine Disorders with MCC), MS-DRG 644 (Endocrine Disorders with CC) and MS-DRG 645 (Endocrine Disorders without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for E21.2?
- The CMS General Equivalence Mappings map E21.2 to ICD-9-CM 252.08.