Diagnosis Coding for Urinary Tract Infections in ICD-10

coding for urinary tract infections
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coding for urinary tract infections

Coding for Urinary Tract Infections in ICD-10-CM

Picture this: A patient rushes into the doctor’s office complaining of a burning sensation during urination and a constant urge to use the bathroom. A urinalysis is performed, and the physician determines the culprit is a urinary tract infection (UTI). Antibiotics are prescribed. This is the point at which the medical coder’s job comes into play. But before we dive into the essential guidelines for successfully coding for UTIs in ICD-10-CM, let’s equip ourselves with the functions of the urinary system and its relationship to this common infectious condition.  

Urinary System and its Function

The urinary system, also called the renal system or urinary tract, comprises the kidneys, ureters, bladder, and urethra. Healthdirect reports that the urinary system’s main function is to remove toxins and wastes from the body in the form of urine. It also controls the chemical and salt levels in the blood, maintains the body’s water balance and vitamin D production for strong, healthy bones, and helps regulate blood pressure and red blood cells.

What is a Urinary Tract Infection?

According to Pathogens, a urinary tract infection (UTI) is one of the most common infectious diseases in the world, affecting 150 million people each year. Anyone can get a UTI, but they are prevalent in women. They occur when a causative agent, usually bacteria, enters the urethra from the skin or rectum and infects a part of the urinary tract, like the urethra, bladder, or kidneys. UTIs negatively impact a person’s relationships, both intimate and social.

General Symptoms of a UTI

Recognizing UTI symptoms is critical for early treatment. According to the Mayo Clinic, when urinary infections cause symptoms, they may include:

  • Frequent urges to urinate (polyuria)
  • Burning feeling while urinating (dysuria)
  • Feeling the need to urinate even when the bladder is empty
  • Cloudy and strong-smelling urine
  • Blood in the urine (hematuria)
  • Pain in the pelvis and around the pubic bone in women

Symptoms Based on Specific Type of UTI

The type of UTI is generally named according to the site of the infection. Specific symptoms may vary based on the infected site and include:

  • Kidney Infection (Pyelonephritis): Pyelonephritis often starts in the bladder and progresses through the ureters to infect one or both kidneys in the upper urinary tract. According to the CDC, this type of kidney infection is less common than a bladder infection but is more serious. Symptoms include upper back and side (flank) pain, high fever, shaking and chills, and nausea or vomiting.
  • Bladder Infection (Cystitis):  The most common type of UTI affecting the bladder and urethra in the lower urinary tract, cystitis presents with symptoms of pelvic pressure, lower abdomen discomfort, frequent and painful urination, and blood in the urine.
  • Urethra Infection (Urethritis): Occurring in the urethra only, urethritis symptoms include burning with urination and discharge.

Causes and Risk Factors of UTIs

The main causative agents of UTIs are bacteria, with Escherichia coli (E. coli) being the most frequent. Other bacteria that may be responsible for a urinary tract infection include Klebsiella pneumonia, Proteus mirabilis, Enterococcus faecalis, and Staphylococcus spp. In rare cases, other microorganisms, such as fungi and some viruses, may result in a UTI.

E. coli is often found in the gastrointestinal (GI) tract. Females have an increased risk of UTIs compared to males because of their anatomy, and sexual intercourse can introduce bacteria. An infection of the urethra can happen when GI bacteria spread from the anus to the urethra. This type of infection can be caused by a sexually transmitted disease such as herpes or gonorrhea. Other factors that can put a person at risk include contraceptive methods, post-menopausal changes, and various health conditions such as urinary tract blockages, diabetes, and recent urinary surgery. 

Diagnosis and Testing

Diagnosing a UTI involves analyzing urine samples for white blood cells, red blood cells, or bacteria. For frequent infections, an ultrasound, computerized tomography (CT) scan, or magnetic resonance imaging (MRI) may be taken of the urinary tract. Additionally, the physician may also use a contrast dye to view the structures in the urinary tract and perform a cystoscopy to see inside the urethra and bladder. This procedure involves the use of a long, thin tube with a lens called a cystoscope. 


Antibiotics are the primary treatment for UTIs, but their use comes with potential side effects. These may range from a minor rash to something more serious, like an antibiotic-resistant infection or Clostridioides difficile (C. diff) infection, which can lead to diarrhea and possibly even severe damage to the colon and death.

Other forms of treatment may include an analgesic to relieve pain while urinating or intravenous antibiotics given in the hospital for severe UTIs.


Untreated UTIs can lead to serious complications such as recurrent infections, kidney damage, and even sepsis. Recurrent UTIs, defined as three or more instances within a year, pose a significant concern. Drug resistance is a common cause of recurrence and complicates treatment, making it increasingly challenging to address UTIs effectively.

coding for urinary tract infections

Diagnosis Coding for UTIs

Coding for urinary tract infections in ICD-10 requires a knowledge of the ICD-10-CM Official Guidelines for Coding and Reporting and the chapter-specific guidelines in Chapter 14, Diseases of the Genitourinary System (N00-N99). The codes for UTIs are located in different blocks within Chapter 14 based on anatomical site. 

Codes for Pyelonephritis (Kidney Infection)

Codes for pyelonephritis are found in block N10-N16, Renal tubulointerstitial diseases, under categories N10-N12: 

  • N10  Acute pyelonephritis
  • N11  Chronic tubulo-interstitial nephritis
  • N12  Tubulo-interstitial nephritis, not specified as acute or chronic

N10 and N12 are billable codes; however, N11 requires a 4th digit to describe the condition in more detail, such as:

  • N11.0, Nonobstructive reflux-associated chronic pyelonephritis
  • N11.1, Chronic obstructive pyelonephritis
  • N11.8, Other chronic tubulointerstitial nephritis
  • N11.9, Chronic tubulointerstitial nephritis, unspecified

Codes for Cystitis (Bladder Infection)

Codes for cystitis are found in block N30-N39, Other Diseases of the Urinary System, under category N30, Cystitis. N30 is further classified into these subcategories:

The above are not billable codes and instead require a 5th digit to describe the condition in more detail. Each child code describes either “without hematuria” or “with hematuria.”

For example, N30.0 has two child codes, N30.00 and N30.01: 

  • N30.00, Acute cystitis without hematuria
  • N30.01, Acute cystitis with hematuria

Codes for Urethritis (Urethra Infection)

Codes for urethritis are located in category N34, Urethritis and urethral syndrome, and are further classified into these codes:

  • N34.0, Urethral abscess
  • N34.1, Nonspecific urethritis
  • N34.2, Other urethritis
  • N34.3, Urethral syndrome, unspecified

If the documentation does not state the site of the infection for the UTI, assign N39.0, Urinary tract infection, site not specified. N39.0 is listed under category N39, Other disorders of urinary system.

Notice there is a “Use additional” code listed for all of the codes listed in the above categories that states: 

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

Therefore, when the documentation states the type of urinary tract infection and the infectious organism, a code from B95-B97 must also be assigned.

Coding for Urosepsis: Urosepsis is a general term, and there is no code for it. If the documentation indicates “urosepsis,” query the physician for more information. 

Coding Exercise

Review the coding exercise below and answer the 7 questions. The answers and rationale are also provided.

A 33-year-old female is seen by her physician with frequent urination and pain and is diagnosed with a urinary tract infection due to E. coli. Antibiotics are prescribed. 

  1. What are the symptoms?
  2. Are they integral to the disease process?
  3. What is the condition?
  4. What is the infectious organism?
  5. Does the documentation indicate that the infection is resistant to antibiotics? 
  6. Is there a history of recurrent UTIs?
  7. What ICD-10-CM code(s) would you assign for this encounter?  


  1. Frequent urination and pain
  2. Yes
  3. Urinary tract infection (UTI)
  4. E. coli
  5. No
  6. No
  7. N39.0, B96.20

Codes and Rationale (#7):

  • N39.0, Urinary tract infection, site not specified
  • B96.20, Unspecified Escherichia coli [E. coli] as the cause of diseases classified elsewhere

Look in the Alphabetic Index under Infection, infected, infective (opportunistic)/Urinary (tract)/urinary tract infection, site not specified N39.0. This code can then be verified in the Tabular as: 

N39.0, Urinary tract infection, site not specified

There is a note at N39 that states: Use additional code (B95-B97) to identify infectious agent.

In the Tabular, we need to choose a code from one of these categories: 

  • B95  Streptococcus, Staphylococcus, and Enterococcus as the cause of diseases classified elsewhere
  • B96  Other bacterial agents as the cause of diseases classified elsewhere
  • B97  Viral agents as the cause of diseases classified elsewhere

In this case, the causal agent is E. coli, a bacterial organism, so we need to look at a code from category B96. Going down the list of codes, we see the subcategory B96.2  Escherichia coli [E. coli] as the cause of diseases classified elsewhere. Looking further at the code selections under B96.2, we can see that the correct code is:

B96.20, Unspecified Escherichia coli [E. coli] as the cause of diseases classified elsewhere

An “unspecified” code is required here due to the fact that there is not enough information to report a more specific type.

Locate and verify: To locate and verify this code in the coding manual, look in the Index under Infection, infected, infective (opportunistic)/Escherichia (E.) coli NEC/as cause of disease classified elsewhere. Again, it takes us to B96.20. 

A note at A00-B99 states: Use additional code to identify resistance to antimicrobial drugs (Z16.-). Nothing in the documentation indicates resistance to a drug, so we cannot code for it. 

Sequencing: The “Use additional code” at N39.0 (UTI) indicates that a secondary code should be added for the infectious agent (E. coli). Also, the ICD-10-CM Official Guidelines for Coding and Reporting tell us when there is a bacterial infection not included in Chapter 1, the coder may need to report a secondary code from B95 or B96 to identify the bacterial organism causing the infection. In the above scenario, the UTI reported with N39.0 is included in Chapter 14 (not Chapter 1), and the causal bacterial organism, E. coli, is reported with B96.20. Therefore, N39.0 should be sequenced first, followed by B96.20.

Integral symptoms: There is no need to assign codes for frequent urination and pain since these symptoms are integral to the urinary tract infection. 

In summary, be sure to review all general and chapter-specific coding guidelines before making your final code selection. Review all the Inclusion terms, Includes, Use additional, Excludes1 and Excludes2 notes.

Want more practice in UTI coding? Go to the multiple-choice Coding Challenge here or the “Name That Code” coding exercise here.

girl with different types of UTIs to help with coding for urinary tract infections in ICD-10
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