2026 ICD-10-CM Diagnosis Code R10.A2Flank pain, left side

ICD-10-CM Codes›R00–R99›R10-R19›R10

ICD-10-CM R10.A2
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R10.A2 is a billable ICD-10-CM diagnosis code for flank pain, left side. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 391 through 392. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established.

Code Identity

ICD-10-CM Code
R10.A2
Billable Status
Yes — Valid for Submission
Code Describes
Flank pain, left side
Short Description
Flank pain, left side
Same as the full description in the CMS dataset.
Parent Code
R10.A
Pain localized to flank

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR10-R19Symptoms and signs involving the digestive system and abdomen
CategoryR10Abdominal and pelvic pain
This CodeR10.A2Flank pain, left side

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Pain(s)
      • flank
        • left

Code History & ChangesHistory

New Code R10.A2 was added to the ICD-10-CM code set for FY 2026, effective October 1, 2025.

Replacement R10.A2 replaces the following previously assigned code(s):

  • R10.84 - Generalized abdominal pain
FY 2026AddedAdded to the ICD-10-CM code setEffective October 1, 2025.
FY 2026CurrentRevised in the current code setEffective October 1, 2025 through September 30, 2026.

Questions About R10.A2Overview

Is R10.A2 (Pain localized to flank) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report flank pain, left side on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does R10.A2 group to?

When flank pain, left side is the principal diagnosis on an inpatient stay, it groups to MS-DRG 391, 392, with relative weights from 0.7796 to 1.2683 depending on complications. Higher weights mean higher Medicare reimbursement.

Can R10.A2 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the flank pain, left side is established, that condition takes the principal position instead.