J12.1
Respiratory syncytial virus pneumonia
J12.1 (also written J121) is a billable ICD-10-CM diagnosis code for respiratory syncytial virus pneumonia. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 8 codes in category J12 (Viral pneumonia, not elsewhere classified). The Alphabetic Index lists it under 7 entries. Its coding notes include a Code first instruction, a Use additional code instruction, a Code also instruction and 28 Excludes2 entries.
Code first
If the underlying condition listed here is present and known, sequence it first.
Use additional code
Add the listed code as a secondary code, if known.
Also from chapter/block level (8 notes)
- code, if applicable, to identify resistance to antimicrobial drugs (Z16.-)
Code also
Two codes may be needed to describe the condition. This note gives no sequencing order.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
- aspiration pneumonia due to anesthesia during labor and delivery (O74.0)
- aspiration pneumonia due to anesthesia during pregnancy (O29)
- aspiration pneumonia due to anesthesia during puerperium (O89.0)
- aspiration pneumonia due to solids and liquids (J69.-)
- aspiration pneumonia NOS (J69.0)
- congenital pneumonia (P23.0)
- congenital rubella pneumonitis (P35.0)
- interstitial pneumonia NOS (J84.9)
- lipid pneumonia (J69.1)
- neonatal aspiration pneumonia (P24.-)
Also from chapter/block level (18 notes)
- 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)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Respiratory clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Hospital MCC
Counts as a major complication or comorbidity (MCC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 121 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CIncludes
Further defines or gives examples of the content of the category.
- bronchopneumonia due to viruses other than influenza viruses
Inclusion terms
Conditions classified to this code.
- RSV pneumonia
Notes
Also from chapter/block level (1 note)
- When a respiratory condition is described as occurring in more than one site and is not specifically indexed, it should be classified to the lower anatomic site (e.g. tracheobronchitis to bronchitis in J40).
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 7 entries
- Infection, infected, infective (opportunistic), virus, viral NOS, respiratory syncytial (RSV), bronchopneumonia
- Infection, infected, infective (opportunistic), virus, viral NOS, respiratory syncytial (RSV), pneumonia
- Pneumonia (acute) (double) (migratory) (purulent) (septic) (unresolved), in (due to), respiratory syncytial virus (RSV)
- Pneumonia (acute) (double) (migratory) (purulent) (septic) (unresolved), respiratory syncytial virus (RSV)
- Pneumonia (acute) (double) (migratory) (purulent) (septic) (unresolved), viral, virus (broncho) (interstitial) (lobar), respiratory syncytial (RSV)
- Virus, viral, respiratory syncytial (RSV), bronchopneumonia
- Virus, viral, respiratory syncytial (RSV), pneumonia