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ICD-10-CM 2027 diagnosis code

N45.1Epididymitis

✓ Billable / specificMale only

N45.1 is a valid, billable ICD-10-CM code for epididymitis. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Didymytis, ICD-10 code for Epididymitis, ICD-10 code for Periepididymitis.

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 N45.1

N45.1 is the ICD-10-CM diagnosis code for epididymitis. It belongs to category N45 (orchitis and epididymitis), block N40-N53 (diseases of male genital organs) and chapter 14 (diseases of the genitourinary system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within N45 (orchitis and epididymitis), N45.1 is specifically for epididymitis. Related codes cover orchitis (N45.2), epididymo-orchitis (N45.3) and abscess of epididymis or testis (N45.4).

Use an additional code (B95-B97), to identify infectious agent.

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 727 (Inflammation of the Male Reproductive System with MCC, relative weight 1.37) and DRG 728 (Inflammation of the Male Reproductive System without MCC, relative weight 0.8224), in MDC 12 (Diseases and Disorders of the Male Reproductive 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.

It is on the CMS list of diagnoses consistent only with male patients (the sex-conflict edit itself was retired in FY2025).

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 604.90 (orchitis and epididymitis, unspecified) and 604.99 (other orchitis, epididymitis, and epididymo-orchitis, without mention of abscess).

Notes that apply from higher levels

Instructions written at a parent level also apply to N45.1.

› From N45 Orchitis and epididymitis
Use additional code
  • code (B95-B97), to identify infectious agent.

Broader instructions also apply from Chapter 14: Diseases of the genitourinary system.

Alphabetic index entries

4 entries

Terms in the official ICD-10-CM index that lead to N45.1.

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.

ICD-9-CM equivalent

Converter →
  • 604.90Orchitis and epididymitis, unspecifiedapproximate
  • 604.99Other orchitis, epididymitis, and epididymo-orchitis, without mention of abscessapproximate

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 N45.1

Is N45.1 billable?

Yes. N45.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can N45.1 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict N45.1 as a principal diagnosis.

Is N45.1 a CC or MCC?

No. N45.1 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does N45.1 group to?

N45.1 is used in the MS-DRG v44.0 logic for MS-DRG 727 (Inflammation of the Male Reproductive System with MCC) and MS-DRG 728 (Inflammation of the Male Reproductive System 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 N45.1?

The CMS General Equivalence Mappings map N45.1 to ICD-9-CM 604.90 and 604.99.