Is ICD-10-CM code R91 billable?

No, R91 (Abnormal findings on diagnostic imaging of lung) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code R91 belong to?

R91 belongs to Chapter 18 of the ICD-10-CM tabular list: R00–R99 (Symptoms, Signs and Abnormal Clinical and Laboratory Findings).

R91Not billable, use a more specific code below

Abnormal findings on diagnostic imaging of lung

In Abnormal findings on diagnostic imaging and in function studies, without diagnosis (R90-R94), chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings

2 billable codes under R91: none are a CC or MCC; none map to an HCC.

Instructional notes

Also applies, from Abnormal findings on diagnostic imaging and in function studies, without diagnosis (R90-R94)

These notes sit on R90-R94 and apply to every code under it, including R91.

Includes: conditions that are coded here

nonspecific abnormal findings on diagnostic imaging by computerized axial tomography [CAT scan]
nonspecific abnormal findings on diagnostic imaging by magnetic resonance imaging [MRI][NMR]
nonspecific abnormal findings on diagnostic imaging by positron emission tomography [PET scan]
nonspecific abnormal findings on diagnostic imaging by thermography
nonspecific abnormal findings on diagnostic imaging by ultrasound [echogram]
nonspecific abnormal findings on diagnostic imaging by X-ray examination

Excludes1: not coded here, use a different code

abnormal findings on antenatal screening of mother (O28.-)
diagnostic abnormal findings classified elsewhere - see Alphabetical Index

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers when to report symptom, sign, and abnormal finding codes (R00-R99), plus specific rules for falls, coma scales, non-infectious SIRS, death NOS, and NIHSS scores.

Use of symptom codes (page 75)
Use of a symptom code with a definitive diagnosis code (page 75)
Combination codes that include symptoms (page 75)
Repeated falls (page 76)
Coma (page 76)
Functional quadriplegia (page 76)
SIRS due to Non-Infectious Process (page 77)
Death NOS (page 77)

Read Section I.C.18 (page 75), 1 more topics

All codes under R91

R91 can't be used on a claim. Pick a billable code below; grey headings group them.

R91 MS-DRGs

As the principal diagnosis, the billable codes under R91 group to MS-DRG 204, 205, or 206 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

DRG 204 Respiratory Signs and Symptoms (1 of 2 codes)
DRG 205 Other Respiratory System Diagnoses with MCC (1 of 2 codes)
DRG 206 Other Respiratory System Diagnoses without MCC (1 of 2 codes)

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.