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ICD-10-CM 2027 diagnosis code

M1A.4591Other secondary chronic gout, unspecified hip, with tophus (tophi)

✓ Billable / specificRequires 7th character

M1A.4591 is a valid, billable ICD-10-CM code for other secondary chronic gout, unspecified hip, with tophus (tophi). It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Other secondary chronic gout, unspecified hip, with tophus

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M1A.4591

M1A.4591 is the ICD-10-CM diagnosis code for other secondary chronic gout, unspecified hip, with tophus (tophi). It belongs to category M1A (chronic gout), block M05-M14 (inflammatory polyarthropathies) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

The 7th character "1" means with tophus (tophi).

Use an additional code to identify: Autonomic neuropathy in diseases classified elsewhere (G99.0), Calculus of urinary tract in diseases classified elsewhere (N22), Cardiomyopathy in diseases classified elsewhere (I43), Disorders of external ear in diseases classified elsewhere (H61.1-, H62.8-), Disorders of iris and ciliary body in diseases classified elsewhere (H22) and 1 more.

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 553 (Bone Diseases and Arthropathies with MCC, relative weight 1.2494) and DRG 554 (Bone Diseases and Arthropathies without MCC, relative weight 0.8331), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 274.03 (chronic gouty arthropathy with tophus (tophi)).

7th character

1with tophus (tophi)

Other encounter types for M1A.459:

Notes that apply from higher levels

Instructions written at a parent level also apply to M1A.4591.

› From M1A.4 Other secondary chronic gout
Code first
  • associated condition
› From M1A Chronic gout
Excludes1
  • gout NOS (M10.-)
Excludes2
  • acute gout (M10.-)
Use additional code
  • code to identify:
  • Autonomic neuropathy in diseases classified elsewhere (G99.0)
  • Calculus of urinary tract in diseases classified elsewhere (N22)
  • Cardiomyopathy in diseases classified elsewhere (I43)
  • Disorders of external ear in diseases classified elsewhere (H61.1-, H62.8-)
  • Disorders of iris and ciliary body in diseases classified elsewhere (H22)
  • Glomerular disorders in diseases classified elsewhere (N08)

Broader instructions also apply from Chapter 13: Diseases of the musculoskeletal system and connective tissue.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

MDC 08 · Diseases and Disorders of the Musculoskeletal System and Connective Tissue

ICD-9-CM equivalent

Converter →
  • 274.03Chronic gouty arthropathy with tophus (tophi)approximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about M1A.4591

Is M1A.4591 billable?

Yes. M1A.4591 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

What does the "1" at the end of M1A.4591 mean?

It is the 7th character for with tophus (tophi).

Can M1A.4591 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict M1A.4591 as a principal diagnosis.

Is M1A.4591 a CC or MCC?

No. M1A.4591 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does M1A.4591 group to?

M1A.4591 is used in the MS-DRG v44.0 logic for MS-DRG 553 (Bone Diseases and Arthropathies with MCC) and MS-DRG 554 (Bone Diseases and Arthropathies without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for M1A.4591?

The CMS General Equivalence Mappings map M1A.4591 to ICD-9-CM 274.03.