R91.1 ICD-10-CM Code: Solitary pulmonary nodule
HCC Buddy Code Card
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FY 2026 Apr update / Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99) / Abnormal findings on diagnostic imaging and in function studies, without diagnosis (R90-R94)
R91.1
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceSolitary pulmonary nodule
A single small rounded spot or nodule found on a chest X-ray or CT scan that requires further evaluation to determine if it is serious.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- Coin lesion lung
- Solitary pulmonary nodule, subsegmental branch of the bronchial tree
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for R91.1 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for R91.1 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for R91.1 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for R91.1 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for R91.1 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for R91.1 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is R91.1 an HCC code?
No. R91.1 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- R91.1
- Description
- Solitary pulmonary nodule
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
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
R91.1 is the ICD-10-CM diagnosis code for solitary pulmonary nodule. A single small rounded spot or nodule found on a chest X-ray or CT scan that requires further evaluation to determine if it is serious. R91.1 sits in the ICD-10-CM chapter for symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (r00-r99), within the section covering abnormal findings on diagnostic imaging and in function studies, without diagnosis (r90-r94).
R91.1 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.
Document the size, location, and characteristics of the nodule; follow-up imaging recommendations should be noted.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for R91.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the size, location, and characteristics of the nodule; follow-up imaging recommendations should be noted
- •This finding often triggers surveillance protocols; ensure appropriate follow-up is documented