2026 ICD-10-CM Diagnosis Code R31.21Asymptomatic microscopic hematuria

ICD-10-CM Codes›R00–R99›R30-R39›R31

ICD-10-CM R31.21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R31.21 is a billable ICD-10-CM diagnosis code for asymptomatic microscopic hematuria. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 695 through 696. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Hematuria.

Code Identity

ICD-10-CM Code
R31.21
Billable Status
Yes — Valid for Submission
Code Describes
Asymptomatic microscopic hematuria
Short Description
Asymptomatic microscopic hematuria
Same as the full description in the CMS dataset.
Parent Code
R31.2
Other microscopic hematuria

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR30-R39Symptoms and signs involving the genitourinary system
CategoryR31Hematuria
This CodeR31.21Asymptomatic microscopic hematuria

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Asymptomatic microscopic hematuria
  • Microscopic hematuria
  • Urine microscopy:RBC's present

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • AMH

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.

    • AMH(asymptomatic microscopic hematuria)
    • Hematuria
      • microscopic NEC (with symptoms)
        • asymptomatic

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR GEN009
Hematuria
Default principal diagnosis: inpatient Yes · outpatient Yes

Convert R31.21 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
599.72 Microscopic hematuria
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement R31.21 replaces the following previously assigned code(s):

  • R31.2 - Other microscopic hematuria
FY 2018AddedAdded to the ICD-10-CM code setEffective October 1, 2017.
FY 2019–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About R31.21Overview

Is R31.21 (Other microscopic hematuria) a billable code?

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

What MS-DRG does R31.21 group to?

When asymptomatic microscopic hematuria is the principal diagnosis on an inpatient stay, it groups to MS-DRG 695, 696, with relative weights from 0.6890 to 1.1438 depending on complications. Higher weights mean higher Medicare reimbursement.

Can R31.21 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the asymptomatic microscopic hematuria is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R31.21?

Under the General Equivalence Mappings, asymptomatic microscopic hematuria converts to ICD-9-CM 599.72 (microscopic hematuria). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.