ICD-10-CM 2027
ICD-10 code for flank pain
From the official ICD-10-CM alphabetic index entry “Pain (s) › flank”. Page updated September 29, 2026.
About coding flank pain
The ICD-10-CM code for flank pain is R10.A0 (Flank pain, unspecified side). The official index lists 3 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on R10.A0.
Within R10.A, choose R10.A0 (unspecified side) only when documentation doesn't support a more specific option: right side (R10.A1), left side (R10.A2) and bilateral (R10.A3).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 391 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC, relative weight 1.2392) and DRG 392 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC, relative weight 0.7645), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific flank pain codes (official index)
Common questions about flank pain ICD-10 codes
What is the ICD-10 code for flank pain?
- R10.A0 — Flank pain, unspecified side. More specific codes apply when the documentation supports them: R10.A3, R10.A2, R10.A1.
What is the ICD-10 code for bilateral flank pain?
- R10.A3 — Flank pain, bilateral.
What is the ICD-10 code for left flank pain?
- R10.A2 — Flank pain, left side.
What is the ICD-10 code for right flank pain?
- R10.A1 — Flank pain, right side.
Is R10.A0 billable?
- Yes. R10.A0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can R10.A0 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict R10.A0 as a principal diagnosis.
Is R10.A0 a CC or MCC?
- No. R10.A0 is neither a CC nor an MCC under MS-DRG v44.0.