I31.9 — Disease of pericardium, unspecified
Is I31.9 billable?
Yes, but I31.9 is an unspecified code. I31.9 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, I31.9 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 I31.9 — the more specific alternatives are listed below.
I31.9 at a glance
| Code | I31.9 |
|---|---|
| Description | Disease of pericardium, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does I31.9 group to?
I31.9 sits in MDC 05 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.
- 314Other Circulatory System Diagnoses with MCCmedical
- 315Other Circulatory System Diagnoses with CCmedical
- 316Other Circulatory System Diagnoses without CC/MCCmedical
As a secondary diagnosis, I31.9 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is I31.9 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to I31.9. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Pericarditis (with decompensation) (with effusion)
- Pericarditis › chronic (with decompensation) (with effusion)
Inclusion terms
Alternative wording in documentation that is classified to I31.9.
- Pericarditis (chronic) NOS
Excludes1 — never code together — inherited from I31
The conditions below can never be reported together with I31.9 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 Chapter 9
The conditions below are not part of I31.9, but a patient may have both at the same time. When documentation supports it, I31.9 and the excluded code may both be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- systemic connective tissue disorders (M30-M36)
- transient cerebral ischemic attacks and related syndromes (G45.-)
How long has I31.9 existed?
I31.9 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.