E21.5 — Disorder of parathyroid gland, unspecified
Is E21.5 billable?
Yes, but E21.5 is an unspecified code. E21.5 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, E21.5 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting E21.5 — the more specific alternatives are listed below.
More specific alternatives
E21.5 at a glance
| Code | E21.5 |
|---|---|
| Description | Disorder of parathyroid gland, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does E21.5 group to?
E21.5 sits in MDC 10 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 643Endocrine Disorders with MCCmedical
- 644Endocrine Disorders with CCmedical
- 645Endocrine Disorders without CC/MCCmedical
How is E21.5 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to E21.5. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Disease, diseased › parathyroid
- Disorder › parathyroid (of)
Excludes1 — never code together — inherited from Chapter 4
The conditions below can never be reported together with E21.5 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- transitory endocrine and metabolic disorders specific to newborn (P70-P74)
Excludes1 — never code together — inherited from E20-E35
The conditions below can never be reported together with E21.5 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes1 — never code together — inherited from E21
The conditions below can never be reported together with E21.5 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes2 — not included here — inherited from E21
The conditions below are not part of E21.5, but a patient may have both at the same time. When documentation supports it, E21.5 and the excluded code may both be reported.
- familial hypocalciuric hypercalcemia (E83.52)
How long has E21.5 existed?
E21.5 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.