Are you tired of dealing with rejected claims and billing errors when coding for Urinary Tract Infections (UTIs)? Accuracy in ICD-10 coding is the key to smooth claim processing, proper reimbursement, and compliance with medical billing standards. With UTIs being one of the most frequently diagnosed infections, coders and healthcare providers must navigate a range of complex scenarios—from acute vs. chronic infections to UTIs complicated by pregnancy, diabetes, or catheter use.
This comprehensive guide breaks down every essential ICD-10 code for UTIs, ensuring you have the right codes for bladder infections (cystitis), kidney infections (pyelonephritis), urethral infections (urethritis), pregnancy-related UTIs, and bacterial-specific cases.
Whether you’re a medical coder, billing specialist, or healthcare provider, this resource will help you code UTIs with accuracy, speed, and confidence—so you can focus on delivering quality patient care without the headache of claim denials.
ICD-10 Code for Unspecified Urinary Tract Infections (UTIs)
When a urinary tract infection (UTI) is diagnosed but the specific location (e.g., bladder, kidney, or urethra) is not documented, the correct ICD-10 code to use is:
- N39.0 – Urinary tract infection, site not specified
Key Considerations:
- Use this code when there is no mention of cystitis, pyelonephritis, or urethritis in the medical documentation.
- Commonly applied in primary care and urgent care settings, where initial diagnoses are made before further testing.
- Always encourage providers to specify the site of infection to improve coding accuracy.
ICD-10 Codes for UTIs Based on Infection Location
The ICD-10 system differentiates between UTIs occurring in the bladder, kidneys, and urethra. Assigning the correct code ensures better claim approval rates and treatment alignment.
1. Bladder Infections (Cystitis)
Cystitis refers to an infection localized in the bladder and can present with or without hematuria (blood in the urine).
- N30.0 – Acute cystitis without hematuria
- N30.01 – Acute cystitis with hematuria
- N30.9 – Cystitis, unspecified
Use Cases:
N30.0 for a straightforward bladder infection with no blood in the urine.
N30.01 when hematuria is documented, as this can indicate a more severe infection.
N30.9 when cystitis is diagnosed, but the provider has not specified whether it’s acute, chronic, or includes hematuria.
2. Kidney Infections (Pyelonephritis)
Pyelonephritis is a serious UTI that spreads to the kidneys, often requiring hospitalization. Proper coding is crucial to differentiate between acute and chronic conditions.
- N10 – Acute pyelonephritis
- N11.0 – Chronic pyelonephritis
- N11.9 – Chronic pyelonephritis, unspecified
Use Cases:
N10 is assigned when a new, severe kidney infection is diagnosed.
N11.0 applies when the patient has a history of repeated kidney infections, leading to chronic damage.
N11.9 should only be used if chronic pyelonephritis is diagnosed but lacks additional details.
Billing Tip: Pyelonephritis often requires hospitalization, so pairing this code with additional treatment and severity codes can ensure proper reimbursement.
3. Urethral Infections (Urethritis)
Urethritis occurs when the infection affects the urethra, sometimes alongside bladder or kidney infections.
- N34.1 – Nonspecific urethritis
- N34.2 – Other urethritis
- N34.3 – Urethral syndrome
Use Cases:
N34.1 is used when the cause of urethritis is unknown (e.g., a bacterial culture has not been performed yet).
N34.2 applies to cases where a different but specified cause is noted (e.g., viral or fungal).
N34.3 is used for patients with symptoms resembling urethritis but without a confirmed bacterial cause.
ICD-10 Coding for Recurrent and Chronic UTIs
Some patients suffer from recurring or chronic UTIs, requiring specific coding to differentiate between ongoing infections, history of infections, and chronic conditions.
1. History of UTIs (No Active Infection)
- Z87.440 – Personal history of urinary (tract) infections
Use Case:
This code is used for patients who have had UTIs in the past but are not currently experiencing an active infection.
2. Recurrent UTIs
- N39.0 – Recurrent UTI (if an active infection is present)
- Z87.440 – Recurrent UTI (if no active infection, but history is noted)
Use Cases:
If a patient presents with a recurrent but active infection, N39.0 should be used.
If the patient has a history of recurrent UTIs but is not currently infected, use Z87.440.
3. Chronic UTIs
- N11.9 – Chronic urinary tract infection, site unspecified
- N11.0 – Chronic pyelonephritis (Kidney infections)
- N30.20 – Other chronic cystitis without hematuria
- N30.21 – Other chronic cystitis with hematuria
Use Cases:
Use N11.9 when a chronic UTI is documented but not site-specific.
Use N11.0 for chronic kidney infections with long-term damage.
Use N30.20 or N30.21 for chronic bladder infections, depending on the presence of hematuria.
Documentation Tip: Encourage detailed provider notes to avoid using unspecified codes, which can affect reimbursement rates.
ICD-10 Coding for UTIs During Pregnancy
Pregnant patients require specific ICD-10 codes that reflect both the infection site and pregnancy trimester.
1. General UTI During Pregnancy
- O23.0 – Infection of the genitourinary tract in pregnancy
2. Trimester-Specific UTI Codes
- O23.01 – UTI in first trimester
- O23.02 – UTI in second trimester
- O23.03 – UTI in third trimester
3. Specific Organ Infections During Pregnancy
- O23.0 – Kidney infection during pregnancy
- O23.1 – Bladder infection during pregnancy
- O23.2 – Urethral infection during pregnancy
- O23.4 – General UTI in pregnancy
- O23.5 – Genital tract infection in pregnancy
Use Cases:
O23.0-O23.03 should be paired with a trimester code for billing accuracy.
O23.1-O23.5 should be used when the infection site is clearly documented.
Billing Tip: Pregnancy-related conditions require specific coding, so double-check provider documentation to ensure proper claim submission.
ICD-10 Coding for UTIs with Identified Bacterial Causes
When a specific bacteria is identified as the cause of a UTI, it is important to use an additional ICD-10 code to document the causative organism. This ensures accurate treatment, proper claim submission, and improved reimbursement rates.
Common Bacterial Causes of UTIs and Their ICD-10 Codes
- B96.2 – Escherichia coli [E. coli] as the cause
- B96.1 – Klebsiella pneumonia as the cause
- B96.4 – Proteus (Mirabilis) as the cause
- B96.20 – Unspecified E. coli as the cause
- B96.5 – Pseudomonas as the cause
- B96.89 – Other specified bacterial agents as the cause
- A49.9 – Bacterial infection, unspecified
How to Use These Codes:
- B96.2 is the most commonly used bacterial UTI code as E. coli is responsible for nearly 80% of UTIs.
- B96.1 is used for Klebsiella pneumoniae-related UTIs, often seen in hospital-acquired infections.
- B96.4 is assigned for Proteus mirabilis, which is linked to UTIs that cause kidney stones.
- B96.5 is used for Pseudomonas-related infections, which can be harder to treat due to antibiotic resistance.
- B96.89 should be used for any other specified bacterial UTI not included above.
- A49.9 is a last-resort code used when the specific bacterial cause is unknown or not documented.
Billing Tip: Always pair the bacterial cause code with the primary UTI diagnosis code (e.g., N39.0, N30.0, N10) to fully document the infection and avoid claim rejections.
Best Practices for ICD-10 Coding of UTIs
Accurate ICD-10 coding for UTIs not only improves reimbursement rates but also ensures compliance with insurance policies and reduces claim denials. Here are some best practices:
- Always Specify the Infection Site When Possible
Many UTI-related ICD-10 codes distinguish between bladder (cystitis), kidneys (pyelonephritis), and urethra (urethritis). Using N39.0 (unspecified UTI) should be a last resort when there is no available documentation on the infection location.
- Include Bacterial Cause Codes When Identified
Pair the appropriate B96.XX code with the UTI primary diagnosis code whenever a bacterial culture identifies the pathogen.
- Document Recurrent vs. Chronic UTIs Clearly
If the UTI is recurrent but not chronic, use N39.0 (active infection) or Z87.440 (history of UTI). If the infection is chronic, use N11.9 (chronic UTI) or a more specific chronic cystitis or pyelonephritis code.
- Use Pregnancy-Specific Codes When Applicable
For pregnant patients, always use O23.XX codes to reflect the UTI’s impact on maternal care and pregnancy complications.
- Ensure Proper Documentation for Trimester-Specific Codes
ICD-10 coding guidelines require trimester-specific codes for pregnancy-related UTIs (O23.01, O23.02, O23.03), so ensure provider documentation specifies the trimester to avoid claim denials.
Common Coding Mistakes to Avoid
Even experienced coders can make errors when documenting UTIs. Here are some of the most frequent mistakes and how to avoid them:
1. Using N39.0 Too Often Instead of a More Specific Code
Solution: Always determine the infection site before assigning the unspecified UTI code (N39.0).
2. Forgetting to Assign a Bacterial Cause Code
Solution: If lab results identify a bacterial cause, always pair it with the UTI diagnosis code (e.g., N39.0 + B96.2 for E. coli UTIs).
3. Missing Pregnancy-Related Codes
Solution: For pregnant patients with a UTI, use O23.XX codes instead of general UTI codes like N39.0.
4. Failing to Differentiate Between Acute and Chronic UTIs
Solution: If a patient has a history of repeated infections, ensure the documentation differentiates between acute (N10, N30.0) and chronic (N11.9, N30.20) cases.
5. Not Assigning a Trimester Code for Pregnancy-Related UTIs
Solution: ICD-10 requires trimester-specific UTI codes (O23.01, O23.02, O23.03)—ensure providers document the correct trimester to prevent claim issues.
Summary
Proper ICD-10 coding for Urinary Tract Infections (UTIs) ensures accurate claim submission, reduced denials, and proper reimbursement. By correctly identifying the infection site, bacterial cause, and patient-specific factors (e.g., pregnancy, chronic conditions), coders can streamline the billing process and avoid costly errors.
Key Takeaways:
- Use N39.0 sparingly—whenever possible, identify the specific site of infection (bladder, kidney, urethra).
- Pair UTI diagnosis codes with bacterial cause codes (B96.XX) when applicable.
- Differentiate between acute, chronic, and recurrent UTIs to ensure coding accuracy.
- For pregnant patients, always use O23.XX codes and assign the correct trimester-specific code.
- Stay updated on ICD-10 guidelines to reduce claim denials and improve reimbursement rates.
By following these best practices, medical coders, billing specialists, and healthcare providers can ensure accuracy, efficiency, and compliance in UTI-related coding.
