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N39.0ICD-10-CM

Urinary tract infection, site not specified

BillableUnchanged since 2015Excludes every site-specific UTI

How the code is built

N

Chapter

Diseases of the genitourinary system

39

Category

Other disorders of urinary system

0

Char 4

Site not specified

Chapter

N00 to N99

Diseases of the genitourinary system

Block

N30 to N39

Other diseases of the urinary system

Billable

Yes

Complete at 4 characters

Use additional

B95 to B97

Identify the infectious agent when known

Excludes1

Pyuria, candidiasis, neonatal UTI

Plus any UTI of a specified site, worded as an open list

Revision history

None since 2015

Descriptor unchanged across every fiscal year

DefinitionCode structureClinical pictureDocumentationDecision guideTabular listComparisonClaim contextDenialsSources

Key takeaways

  • N39.0 codes a urinary tract infection when the provider documented a UTI but never named the site
  • Assign it only when the record leaves the location unstated, since cystitis, urethritis, and pyonephrosis each have their own code
  • When a culture identifies the organism, a code from B95 to B97 is added after N39.0
  • The Excludes1 note blocks pyuria, candidiasis, neonatal UTI, and any UTI of a specified site
  • It is billable, and it is the code auditors examine first when a practice reports it at high volume
1Definition

What ICD-10 code N39.0 means

N39.0 is the ICD-10-CM code for urinary tract infection, site not specified. It applies when a provider documents a UTI without identifying where in the urinary tract the infection is located, which is the ordinary situation in primary care, urgent care, and the emergency department when treatment begins before imaging or specialty evaluation.

The phrase "site not specified" is the whole test. Once the record names the bladder, the urethra, or the kidney, a more specific code exists, and N39.0 becomes incorrect rather than merely imprecise.

Code

N39.0

Descriptor

Urinary tract infection, site not specified

Chapter

Diseases of the genitourinary system

Block

Other diseases of the urinary system

Category

N39, other disorders of urinary system

Billable

Yes

Use additional

A code from B95 to B97 to identify the infectious agent

Excludes1

Candidiasis of urinary tract, neonatal UTI, pyuria, and UTI of a specified site

The descriptor has not changed in any fiscal year since ICD-10-CM took effect in 2015. Several published summaries claim a recent update added an Excludes1 note to this code. That is wrong, and the tabular list confirms it. The notes at N39.0 have been stable throughout, which means a coder working from an old reference is not the risk here. Working from habit is.

2Code structure

Where the specificity actually lives

N39.0 has no subdivisions. There is no fifth character, no severity axis, and no laterality. Everything that makes a urinary infection specific sits outside this code, in two directions.

Site

a different code entirely

Site not stated

N39.0

Bladder, meaning cystitis

N30.-, subdivided by acuity and by hematuria

Urethra, meaning urethritis

N34.-

Kidney, meaning acute pyelonephritis

N10

Kidney, pyelonephritis with no acuity stated

N12, where pyelonephritis NOS classifies

Kidney with obstruction and infection

N13.6, pyonephrosis

Kidney infection NOS

N15.9, which carries its own Excludes1 against N39.0

Organism

an additional code alongside

When a culture identifies the pathogen, a code from B95 to B97 is added after N39.0. E. coli, Klebsiella, Pseudomonas, Enterococcus, and Staphylococcus each have an entry. The organism code is always secondary and never leads.

That last kidney row is the trap. Infection of kidney NOS classifies to N15.9, and N15.9 carries an Excludes1 pointing straight back at N39.0. A note saying "kidney infection" is not a UTI with an unstated site. It is a documented site, and the two codes cannot be reported together.

3Clinical picture

Clinical findings documented under N39.0

A record supporting this code describes urinary symptoms with laboratory or clinical evidence of infection, and stops short of localizing it.

Voiding symptoms

Dysuria, urgency, frequency, hesitancy

Urine character

Cloudy or malodorous urine, gross hematuria

Systemic signs

Fever, chills, malaise

Abdominal

Suprapubic pain or pressure

Laboratory

Positive leukocyte esterase or nitrites, pyuria on microscopy, positive culture

Older adults

Presentations are often atypical, though confusion alone with a positive culture does not establish a UTI

Flank pain and costovertebral angle tenderness point toward the kidney. When those appear alongside a documented diagnosis of pyelonephritis, the encounter has left N39.0 behind.

4Documentation

What the chart must show

  • A provider-stated diagnosis of urinary tract infection, not a lab value or a symptom alone
  • Whether the site was identified, since the absence of a site is what makes this code correct
  • Urinalysis and culture results, including the organism when one grew
  • Symptoms supporting active infection, distinguishing it from colonization
  • Catheter status, since an indwelling catheter changes the sequencing entirely
  • Pregnancy status, since a pregnant patient never reports to this code
  • Recurrence, when the provider documents a recurrent or chronic pattern
  • Any link to sepsis, stated explicitly rather than implied by vital signs

Urosepsis is the term that wrecks these charts. It has no default code in the Alphabetic Index, it is not synonymous with sepsis, and the Official Guidelines direct a query rather than an assumption. A coder who reads urosepsis and reports N39.0 has guessed, and a coder who reports A41.9 has guessed in the more expensive direction.

5Decision guide

When to assign N39.0, and when not to

UTI, no site named

N39.0

UTI due to E. coli, no site named

N39.0, then the B96.2- organism code

Acute cystitis

N30.0-, with the hematuria character

Acute pyelonephritis

N10

Pyelonephritis, no acuity stated

N12

Urethritis

N34.-

Kidney infection, no further detail

N15.9, never N39.0

Positive culture, no symptoms, no UTI diagnosis

R82.71, bacteriuria

Pyuria alone, no UTI diagnosis

R82.81

UTI in a pregnant patient

O23.4-, with the trimester character, plus the organism code

Catheter-associated UTI

The catheter complication code first, then N39.0

Sepsis due to a UTI

The sepsis code first, then N39.0

Urosepsis

Not codable, query the provider

UTI in a newborn

P39.3

Sequencing follows one pattern. When something caused the urinary infection, that cause leads. A catheter complication, a pregnancy, or systemic sepsis is sequenced ahead of N39.0, and the UTI code follows as the localized infection.

Query rather than default when the note says urosepsis, reports a positive culture with no diagnosis attached, or describes flank pain and fever without naming pyelonephritis.

6Tabular list

Instructional notes at N39.0 and above

Use additional

A code from B95 to B97 to identify the infectious agent

Excludes1 at N39.0

Candidiasis of urinary tract (B37.4-), neonatal urinary tract infection (P39.3), pyuria (R82.81), and urinary tract infection of a specified site, given as cystitis (N30.-), pyonephrosis (N13.6), and urethritis (N34.-)

Excludes2 at N39

Hematuria NOS (R31.-), recurrent or persistent hematuria (N02.-), proteinuria NOS (R80.-)

Excludes2 at N30 to N39

Urinary infection complicating abortion, ectopic or molar pregnancy (O00 to O07, O08.8), and complicating pregnancy, childbirth and the puerperium (O23.-, O75.3, O86.2-)

Excludes1 at N15.9

Urinary tract infection NOS (N39.0), pointing back at this code

The two note types behave in opposite ways, and the difference decides real claims. Excludes1 is a prohibition, so N39.0 and cystitis never appear together on a claim, and neither do N39.0 and pyuria. Excludes2 is a permission, so a patient with a UTI and separately documented hematuria may carry codes from both.

The pregnancy note deserves particular attention because it is widely misreported as an Excludes1. It is an Excludes2 at the block level. The reason a pregnant patient does not get N39.0 is not that the note forbids it, but that Chapter 15 codes take sequencing priority and O23.4- already describes the condition.

7Comparison

Codes frequently confused with N39.0

N30.-

Descriptor

Cystitis, subdivided by acuity and hematuria

Use instead when

The bladder is named as the site

N34.-

Descriptor

Urethritis and urethral syndrome

Use instead when

The urethra is named as the site

N10

Descriptor

Acute pyelonephritis

Use instead when

Pyelonephritis is documented as acute

N11.-

Descriptor

Chronic tubulo-interstitial nephritis

Use instead when

Pyelonephritis is documented as chronic

N12

Descriptor

Tubulo-interstitial nephritis, not specified as acute or chronic

Use instead when

Pyelonephritis is documented with no acuity, since pyelonephritis NOS classifies here

N13.6

Descriptor

Pyonephrosis

Use instead when

Obstructive uropathy with infection is documented

N15.9

Descriptor

Renal tubulo-interstitial disease, unspecified

Use instead when

The note says kidney infection with no further detail

R82.71

Descriptor

Bacteriuria

Use instead when

A culture is positive, but no UTI was diagnosed

R82.81

Descriptor

Pyuria

Use instead when

Pus cells are reported without a UTI diagnosis

B37.4-

Descriptor

Candidiasis of other urogenital sites

Use instead when

The organism is Candida, which excludes N39.0

O23.4-

Descriptor

Unspecified infection of urinary tract in pregnancy

Use instead when

The patient is pregnant

P39.3

Descriptor

Neonatal urinary tract infection

Use instead when

The patient is a newborn

B95 to B97

Descriptor

Bacterial and viral infectious agents

Use instead when

An organism was identified, added after N39.0

Z87.440

Descriptor

Personal history of urinary tract infections

Use instead when

The infection has resolved and is being reported as history

8Claim context

Services commonly reported with N39.0

N39.0 is overwhelmingly an outpatient diagnosis. It supports office and urgent care evaluation and management, emergency department visits, and telehealth encounters for uncomplicated presentations, each governed by its own documentation and time rules rather than by the diagnosis.

The diagnostic services attached to it draw more scrutiny than the visit does. Urinalysis, reflex culture, and susceptibility testing each require medical necessity supported by documented symptoms, and reflex protocols that culture every specimen automatically are a recurring audit target. When the encounter is inpatient, N39.0 anchors a kidney and urinary tract infection group whose weight depends on complications reported alongside it.

Coverage and frequency rules for urine culture and susceptibility testing vary by Medicare Administrative Contractor, so confirm the applicable local coverage determination before submission.

9Denials

Coding errors that cause denials

Defaulting to N39.0 when the note documents cystitis, urethritis, or pyelonephritis

Assign the site-specific code, since the Excludes1 makes N39.0 incorrect rather than vague

Reporting N39.0 with pyuria (R82.81) or a site-specific UTI code

Choose one, since the Excludes1 note prohibits the pair

Coding N39.0 from a positive culture with no provider diagnosis

Assign R82.71 for bacteriuria, or query for a diagnosis

Coding urosepsis as either N39.0 or a sepsis code

Query the provider, since the term has no default code

Using N39.0 for a pregnant patient

Assign the O23.4- code, which takes sequencing priority

Omitting the organism code after a positive culture

Add the applicable B95 to B97 code as a secondary

Sequencing N39.0 first for a catheter-associated infection

Sequence the catheter complication code first

Coding kidney infection NOS as N39.0

Assign N15.9, which carries an Excludes1 against this code

10Sources

Where to verify N39.0

ICD-10-CM Official Guidelines for Coding and Reporting

The urosepsis query requirement and the rules for coding from lab findings

The ICD-10-CM Tabular List at N39 and N30 to N39

The full Excludes1 list, the use of additional instruction, and the block-level pregnancy note

The CMS ICD-10 code page

Current code files and the annual addenda

AHA Coding Clinic

Published advice on urosepsis, catheter-associated infections, and asymptomatic bacteriuria

Local coverage determinations from the applicable MAC

Urine culture and susceptibility testing medical necessity

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Last reviewed August 2026

This page is a free reference for billing and coding teams and is not coding, legal, or clinical advice. Code selection depends on the documentation in the record and on the policy of the payer being billed. Verify every code, instructional note, and sequencing rule against the current ICD-10-CM files and the Official Guidelines for Coding and Reporting for the applicable date of service. ICD-10-CM is maintained by the CDC's National Center for Health Statistics and published by CMS. CPT is a registered trademark of the American Medical Association. TruCare is not affiliated with CMS, NCHS, the AHA, or the AMA.

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