In 2025, the primary ICD-10-CM code for a urinary tract infection (UTI) without a specified site is N39.0 — “Urinary tract infection, site not specified.”
For more precise documentation, codes like N10 (acute pyelonephritis), N30.00–N30.91 (cystitis), and O23.0 (UTI in pregnancy) should be used, depending on the location and clinical context of the infection.
Quick Summary Table
| Type of UTI | ICD-10-CM Code | Description |
|---|---|---|
| Unspecified UTI | N39.0 | Urinary tract infection, site not specified |
| Acute pyelonephritis | N10 | Infection of kidney and renal pelvis |
| Chronic pyelonephritis | N11.1 | Chronic infection of kidney due to reflux |
| Cystitis (acute) | N30.00 | Acute cystitis without hematuria |
| Cystitis (with hematuria) | N30.01 | Acute cystitis with hematuria |
| Recurrent UTI | N39.0 with additional history code | Multiple infections over time |
| UTI in pregnancy | O23.0–O23.9 | Urinary tract infection complicating pregnancy |
| Catheter-associated UTI (CAUTI) | T83.511A | Infection due to indwelling catheter, initial encounter |
1. Why ICD-10 Coding Accuracy for UTI Matters in 2025
UTIs remain among the most common bacterial infections worldwide, accounting for over 8 million outpatient visits annually in the United States alone.
As healthcare reimbursement, clinical analytics, and AI-driven billing systems become more complex in 2025, the accuracy of ICD-10-CM coding for UTIs directly impacts:
- Insurance reimbursement
- Denial prevention
- Clinical documentation integrity (CDI)
- Patient care continuity
An incorrect or incomplete code can trigger claim denials, data errors in public health reporting, and misaligned treatment metrics.
2. Understanding ICD-10-CM and Its Role
The ICD-10-CM (International Classification of Diseases, 10th Revision, Clinical Modification) is the standardized system used in the U.S. to code and classify diseases, symptoms, and health conditions.
Every diagnosis, from a minor infection to complex conditions, is assigned a code that:
- Defines the condition for clinical and billing purposes
- Links treatment procedures to diagnoses
- Supports data tracking for quality improvement, research, and epidemiology
The ICD-10 system replaced ICD-9 in 2015, offering more specificity and flexibility. As of 2025, the CDC and CMS continue to issue annual updates every October, refining infection-related codes like those for UTIs.
3. The Primary ICD-10 Code for UTI: N39.0
The default ICD-10-CM code for urinary tract infection is N39.0.
Full code description:
N39.0 — Urinary tract infection, site not specified.
Clinical Usage:
This code is used when the infection’s exact location (bladder, urethra, or kidneys) is not documented or cannot be determined at the time of diagnosis.
Example:
A patient presents with burning urination, fever, and positive urine culture but no imaging or site-specific evidence. The provider documents only “UTI.”
→ Correct ICD-10-CM code: N39.0
Coding Note:
If the site is specified (such as cystitis or pyelonephritis), do not use N39.0. Use the appropriate site-specific code for better specificity and reimbursement accuracy.
4. Site-Specific ICD-10-CM Codes for UTI in 2025
When documentation specifies the infected site, coders should use a more accurate code from the N10–N30 range.
a. Pyelonephritis (Kidney Infection)
| Type | ICD-10 Code | Description |
|---|---|---|
| Acute pyelonephritis | N10 | Acute infection of renal pelvis and kidney |
| Chronic pyelonephritis | N11.1 | Chronic pyelonephritis with reflux |
| Pyeloureteritis cystica | N11.8 | Other chronic infections of the kidney |
Clinical example:
CT scan confirms inflammation of the kidney due to E. coli infection.
→ Code: N10 (Acute pyelonephritis)
b. Cystitis (Bladder Infection)
| Type | ICD-10 Code | Description |
|---|---|---|
| Acute cystitis without hematuria | N30.00 | Inflammation of the bladder |
| Acute cystitis with hematuria | N30.01 | Infection accompanied by blood in urine |
| Interstitial cystitis (chronic) | N30.10–N30.11 | Chronic inflammatory bladder condition |
| Trigonitis | N30.30 | Inflammation of bladder trigone |
Example:
Female patient reports dysuria and suprapubic pain; urinalysis positive for bacteria and blood.
→ Code: N30.01 (Acute cystitis with hematuria)
c. Urethritis (Urethral Infection)
| ICD-10 Code | Description |
|---|---|
| N34.1 | Nonspecific urethritis |
| N34.2 | Other urethritis |
| N34.3 | Urethral syndrome, unspecified |
d. Recurrent UTI
There is no standalone code for recurrent UTI.
Coders should use N39.0 for the infection and add Z87.440 to indicate personal history of recurrent UTI.
Example:
Patient with three UTIs in the past six months.
→ Codes: N39.0 and Z87.440
e. UTI in Pregnancy
| ICD-10 Code | Description |
|---|---|
| O23.0 | UTI in pregnancy, first trimester |
| O23.1 | UTI in pregnancy, second trimester |
| O23.2 | UTI in pregnancy, third trimester |
| O23.9 | UTI in pregnancy, unspecified trimester |
Coding Tip:
Always list the pregnancy complication code (O23.x) as the principal diagnosis, followed by N39.0 or a site-specific UTI code.
f. Catheter-Associated UTI (CAUTI)
| ICD-10 Code | Description |
|---|---|
| T83.511A | Infection due to indwelling urinary catheter, initial encounter |
| T83.511D | Subsequent encounter |
| T83.511S | Sequela of catheter-associated infection |
Example:
Hospitalized patient develops UTI three days after catheter insertion.
→ Code: T83.511A + N39.0
5. ICD-10 Coding Scenarios and Clinical Examples
Scenario 1: Simple UTI
Documentation: “Acute urinary tract infection, unspecified site.”
Code: N39.0
Scenario 2: Cystitis with Hematuria
Documentation: “Acute cystitis with visible blood in urine.”
Code: N30.01
Scenario 3: UTI During Pregnancy (Second Trimester)
Documentation: “UTI complicating pregnancy, second trimester.”
Code: O23.1 + N39.0
Scenario 4: Recurrent UTI
Documentation: “Recurrent urinary tract infection.”
Code: N39.0 + Z87.440
Scenario 5: Catheter-Associated Infection
Documentation: “UTI caused by indwelling Foley catheter.”
Code: T83.511A + N39.0
6. Coding Guidelines for 2025
The 2025 ICD-10-CM Official Guidelines for Coding and Reporting emphasize:
- Specificity first — always use the most detailed code possible.
- Link causative organisms when documented (e.g., “E. coli UTI”).
- Add B96.20–B96.29 for Escherichia coli as the cause.
- Example: N39.0 + B96.20
- Sequence pregnancy-related codes before the UTI code.
- Never use N39.0 if a more specific code (e.g., N30.0, N10) is supported by documentation.
- Differentiate between acute and chronic infections when noted.
7. Common Coding Errors and How to Avoid Them
| Mistake | Why It’s Wrong | Correct Approach |
|---|---|---|
| Using N39.0 for all UTIs | Too generic | Use site-specific code if available |
| Missing organism linkage | Reduces data accuracy | Add secondary code (e.g., B96.20) |
| Forgetting pregnancy status | Impacts DRG payment | Add O23.x |
| Incorrect sequencing | Denial risk | Use principal diagnosis logic |
| Ignoring laterality or chronicity | Low-quality documentation | Always verify provider notes |
8. UTI Coding and Reimbursement Impact
Payers rely on ICD-10 codes to determine medical necessity and reimbursement eligibility.
Inaccurate coding may trigger:
- Claim denials or delays
- Lower DRG assignment
- Reduced hospital reimbursement
- Audit red flags
For example:
- Coding N39.0 instead of N30.01 (acute cystitis with hematuria) may lead to lower reimbursement because the latter reflects a higher complexity of care.
9. CDI (Clinical Documentation Improvement) and AI Integration
As of 2025, AI-assisted EHR systems analyze documentation to suggest auto-coded ICD-10 entries.
However, human validation remains critical because AI can miss contextual nuances, such as distinguishing between a recurrent infection and a catheter-associated case.
Strong CDI practices ensure:
- Complete provider documentation
- Clear infection site specification
- Identification of complicating factors (pregnancy, chronic disease, catheter use)
This is essential for accurate HCC (Hierarchical Condition Category) scoring and risk adjustment in value-based care programs.
10. Linking ICD-10 Codes with CPT and Treatment
In billing, ICD-10-CM codes justify the medical necessity of CPT (procedure) codes.
For UTIs, typical CPT combinations include:
| Procedure | CPT Code | Linked ICD-10 Code |
|---|---|---|
| Urinalysis | 81001 | N39.0 or N30.0 |
| Urine culture | 87086 | N39.0 |
| Office visit (new patient) | 99203–99205 | N39.0 |
| Office visit (established) | 99213–99215 | N39.0 or site-specific code |
Documentation Tip:
Always include supporting clinical details (symptoms, lab results, or imaging) to justify the diagnosis and link it to procedures accurately.
11. Trends in UTI Coding and Care (2025 Update)
- AI-driven urine culture analysis is improving diagnostic speed.
- Telehealth has made UTI consultations faster, but coders must confirm clinical validation (symptoms, lab confirmation).
- New antimicrobial stewardship protocols emphasize coding of resistant strains (use Z16.xx).
- CMS audits have increased scrutiny of N39.0 overuse, promoting documentation precision.
Healthcare systems are also adopting data mining algorithms to detect UTI recurrence and prevent CAUTI in long-term care facilities.
12. Compliance and Audit Preparedness
To stay audit-ready:
- Maintain signed provider notes detailing infection site, organism, and treatment plan.
- Review annual ICD-10-CM updates from CMS and CDC.
- Validate sequencing between primary and secondary codes.
- Implement regular CDI audits for infection-related cases.
Consistent documentation helps prevent RAC audit flags and ensures compliance with HIPAA and OIG standards.
13. Summary: Choosing the Correct UTI ICD-10 Code
| Clinical Situation | Correct ICD-10 Code |
|---|---|
| UTI, site not specified | N39.0 |
| Acute cystitis without hematuria | N30.00 |
| Acute cystitis with hematuria | N30.01 |
| Acute pyelonephritis | N10 |
| Chronic pyelonephritis | N11.1 |
| UTI due to catheter | T83.511A + N39.0 |
| UTI in pregnancy (second trimester) | O23.1 + N39.0 |
| Recurrent UTI | N39.0 + Z87.440 |
| UTI due to E. coli | N39.0 + B96.20 |
14. Expert Recommendations
- Always document the site, cause, and chronicity of infection.
- Include organism linkage whenever possible.
- Train providers on coding-specific language (“acute cystitis” vs. “UTI”) to improve data precision.
- Review ICD-10-CM updates annually to align with reimbursement changes.
Accurate UTI coding ensures compliance, protects revenue, and improves patient outcomes.
People Also Ask
N39.0 — Urinary tract infection, site not specified.
N39.0 is for unspecified site infections; N30.0 is for bladder (cystitis).
Yes, but pair it with Z87.440 for recurrent history.
T83.511A for catheter infection and N39.0 for the UTI itself.
O23.0–O23.9 depending on the trimester.
Final Takeaway
In 2025, accurate ICD-10-CM coding for urinary tract infections requires specificity, documentation clarity, and organism linkage.
While N39.0 remains the general code, coders should prioritize site-specific options like N10 or N30.01 whenever possible.
Precision not only improves clinical accuracy but also enhances reimbursement integrity and compliance in an AI-driven healthcare system.
Author Bio
Written by [Mark], a certified medical coding and healthcare documentation specialist with expertise in ICD-10-CM updates, CDI compliance, and healthcare content strategy.