N39.0ICD-10-CM

Urinary tract infection, site not specified

BillableUnchanged since 2015Excludes every site-specific UTI

How the code is built

Chapter

Diseases of the genitourinary system

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.

Attribute	Detail
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

Documented location	Code
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

The record says	Assign
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

Note	Content
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

Code	Descriptor	Use instead when
N30.-	Cystitis, subdivided by acuity and hematuria	The bladder is named as the site
N34.-	Urethritis and urethral syndrome	The urethra is named as the site
N10	Acute pyelonephritis	Pyelonephritis is documented as acute
N11.-	Chronic tubulo-interstitial nephritis	Pyelonephritis is documented as chronic
N12	Tubulo-interstitial nephritis, not specified as acute or chronic	Pyelonephritis is documented with no acuity, since pyelonephritis NOS classifies here
N13.6	Pyonephrosis	Obstructive uropathy with infection is documented
N15.9	Renal tubulo-interstitial disease, unspecified	The note says kidney infection with no further detail
R82.71	Bacteriuria	A culture is positive, but no UTI was diagnosed
R82.81	Pyuria	Pus cells are reported without a UTI diagnosis
B37.4-	Candidiasis of other urogenital sites	The organism is Candida, which excludes N39.0
O23.4-	Unspecified infection of urinary tract in pregnancy	The patient is pregnant
P39.3	Neonatal urinary tract infection	The patient is a newborn
B95 to B97	Bacterial and viral infectious agents	An organism was identified, added after N39.0
Z87.440	Personal history of urinary tract infections	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

Error	Correction
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.