J21.9 — Acute bronchiolitis, unspecified
Is J21.9 billable?
Yes, but J21.9 is an unspecified code. J21.9 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, J21.9 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 J21.9 — the more specific alternatives are listed below.
J21.9 at a glance
| Code | J21.9 |
|---|---|
| Description | Acute bronchiolitis, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does J21.9 group to?
J21.9 sits in MDC 04 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 202Bronchitis and Asthma with CC/MCCmedical
- 203Bronchitis and Asthma without CC/MCCmedical
As a secondary diagnosis, J21.9 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is J21.9 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to J21.9. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Bronchiolitis (acute) (infective) (subacute)
- Bronchiolitis › with › bronchospasm or obstruction (acute) (infective) (subacute)
- Bronchospasm › with › bronchiolitis, acute (acute)
Excludes1 — never code together
The conditions below can never be reported together with J21.9 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- chronic bronchiolitis (J44.89)
Inclusion terms
Alternative wording in documentation that is classified to J21.9.
- Bronchiolitis (acute)
Use additional code — inherited from Chapter 10
Report an additional code alongside J21.9 to fully describe the condition. J21.9 is sequenced first.
Excludes2 — not included here — inherited from Chapter 10
The conditions below are not part of J21.9, but a patient may have both at the same time. When documentation supports it, J21.9 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)
- smoke inhalation (T59.81-)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Excludes2 — not included here — inherited from J20-J22
The conditions below are not part of J21.9, but a patient may have both at the same time. When documentation supports it, J21.9 and the excluded code may both be reported.
- chronic obstructive pulmonary disease with acute lower respiratory infection (J44.0)
Excludes2 — not included here — inherited from J21
The conditions below are not part of J21.9, but a patient may have both at the same time. When documentation supports it, J21.9 and the excluded code may both be reported.
- respiratory bronchiolitis interstitial lung disease (J84.115)
How long has J21.9 existed?
J21.9 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.