J18.9 ICD-10-CM Code: Pneumonia, unspecified organism
HCC Buddy Code Card
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FY 2026 Apr update / Diseases of the respiratory system (J00-J99) / Influenza and pneumonia (J09-J18)
J18.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidancePneumonia, unspecified organism
Pneumonia (lung infection) when neither the specific type nor the causative organism has been identified or documented.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for J18.9 in this effective period.
Excludes 2
Official- abscess of lung with pneumonia (J85.1)
- 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.-)
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for J18.9 in this effective period.
Excludes 1
Official- congenital pneumonia (P23.0)
- drug-induced interstitial lung disorder (J70.2-J70.4)
- interstitial pneumonia NOS (J84.9)
- neonatal aspiration pneumonia (P24.-)
- pneumonitis due to fumes and vapors (J68.0)
Code First
Official- , if applicable, associated influenza (J09.X1, J10.0-, J11.0-)
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for J18.9 in this effective period.
Code Also
Official- , if applicable, any associated condition such as:
- aspiration pneumonia (J69.-)
Buddy Documentation Tip
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is J18.9 an HCC code?
No. J18.9 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
J18.9 is the ICD-10-CM diagnosis code for pneumonia, unspecified organism. Pneumonia (lung infection) when neither the specific type nor the causative organism has been identified or documented. J18.9 sits in the ICD-10-CM chapter for diseases of the respiratory system (j00-j99), within the section covering influenza and pneumonia (j09-j18).
J18.9 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
This is the least specific pneumonia code; use only when no additional information about organism or type is available.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for J18.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is the least specific pneumonia code; use only when no additional information about organism or type is available
- •Query the provider if organism identification is pending or if more clinical detail can clarify the pneumonia type