Diagnosis Coding for Urinary Tract Infections in ICD-10

urinary system and urinary tract coding in ICD-10
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If a patient consults her physician regarding a burning sensation during urination and an intense urge to urinate, it’s possible that she is experiencing a urinary tract infection. In the event that a urinary tract infection is confirmed as the diagnosis, specific guidelines within ICD-10-CM must be adhered to by the medical coder. You’ve arrived at the right place to learn about these essential guidelines.

Urinary Tract Infections

Urinary tract infections (UTIs) are one of the most common, recurrent bacterial infections in individuals, mostly women. Bacteria, such as Escherichia coli (E. coli), enter the urethra and infect one or several parts of the urinary tract, including the urethra, bladder, ureters, or kidneys. UTIs can be mild to serious and even result in death.

The most common type of urinary tract infection is a bladder infection, called cystitis. It affects the bladder and urethra in the lower urinary tract.

A UTI that occurs in the urethra only is called urethritis.

A kidney infection called pyelonephritis often starts in the bladder and then progresses through the ureters to infect one or both kidneys in the upper urinary tract. Pyelonephritis is less common than a bladder infection but is more serious.

According to the U.S. National Library of Medicine: 

  • A urinary tract infection (UTI) is caused by Escherichia coli approximately 80 percent of the time. 
  • The annual occurrence of UTIs diagnosed by physicians in the U.S. is more than 10 percent for females and 3 percent for males.
  • More than 60 percent of females will be diagnosed with a UTI at some point in their lives. 
  • More than 30 percent of females will suffer from a subsequent infection within 12 months of the initial symptoms being resolved despite the appropriate antibiotic. 

Recurrent UTIs are defined as three or more UTIs during a 12-month period. One of the reasons for a recurrent UTI may be drug resistance, as many urinary tract infections are resistant to certain antibiotics. This resistance makes it increasingly difficult to treat UTIs.

Symptoms of UTI

Urinary tract infections do not always cause signs and symptoms. When they do, however, 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

More specific signs and symptoms of a UTI may vary based on the part of the urinary tract infected and include:

Kidney Infection (Pyelonephritis):

  • Upper back and side (flank) pain
  • High fever
  • Shaking and chills
  • Nausea or vomiting

Bladder Infection (Cystitis): 

  • Pelvic pressure
  • Lower abdomen discomfort
  • Frequent, painful urination
  • Blood in urine

Urethra Infection (Urethritis):

  • Burning with urination
  • Discharge
diagram of urinary tract and urinary tract infections in ICD-10


Typically, urinary tract infections occur when bacteria, such as E. coli, enter the urinary tract by way of the urethra and start to multiply in the bladder. If the infection goes untreated, it can progress into the kidneys.

Females have an increased risk of UTIs compared to males because of their anatomy. A woman’s urethra is shorter and closer to the rectum, making it easier for bacteria to get into the urinary tract. 

Sexual intercourse can also introduce bacteria into the urinary tract and can be associated with sexually transmitted infections, such as herpes, gonorrhea, chlamydia, and mycoplasma.

Urethritis occurs in both males and females and is strongly associated with sexually transmitted infections. 

Risk Factors

Individuals who are at an increased risk for urinary tract infections include those who use diaphragms for birth control and spermicidal agents and women who are post-menopause. This is due to a decline in circulating estrogen.

Other risk factors for UTIs include urinary tract abnormalities, blockages in the urinary tract, diabetes and other diseases that impair the immune system, catheter use, and recent urinary surgery or urinary tract exam using medical instruments.  


Lower urinary tract infections rarely lead to complications when immediate treatment is provided. However, left untreated, a UTI can lead to serious complications, which may include:

  • Recurrent infections
  • Permanent kidney damage from an acute or chronic kidney infection (pyelonephritis) due to an untreated UTI
  • Low birth weight or premature birth of infant delivered in pregnant women
  • Urethral narrowing, or stricture, in men from recurrent urethritis, previously seen with gonococcal urethritis
  • Sepsis is a potentially life-threatening condition when the body’s response to an infection damages its tissues. This mostly occurs when the infection goes up the urinary tract to the kidneys. 

Diagnosing a UTI

The physician may ask for a urine sample to look for white blood cells, red blood cells, or bacteria. Sometimes a urine culture may follow to determine the specific bacteria that is causing the infection and the most appropriate medications.

For frequent infections, an ultrasound, computerized tomography (CT) scan, or magnetic resonance imaging (MRI) may be taken of the urinary tract. 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 often the first course of treatment for urinary tract infections. An analgesic may also be prescribed to relieve the pain while urinating. Severe UTIs may require intravenous antibiotics given in a hospital.

Antibiotics can have their own side effects. They may be something as minor as a rash, or 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.

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

  • N30.1, Interstitial cystitis (chronic)
  • N30.2, Other chronic cystitis
  • N30.3, Trigonitis
  • N30.4, Irradiation cystitis
  • N30.8, Other cystitis
  • N30.9, Cystitis, unspecified

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

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.

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. Then compare your answers to the answers and rationale 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

B96.20 can also be found by looking 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. 

There is also a note at A00-B99 that 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. 

As to sequencing, the “Use additional code” indicates that a secondary code should be added. Also, the ICD-10-CM Official Guidelines for Coding and Reporting states:

“… for bacterial infections that are not included in chapter 1, a secondary code from category B95, Streptococcus, Staphylococcus, and Enterococcus, as the cause of diseases classified elsewhere, or B96, Other bacterial agents as the cause of diseases classified elsewhere, may be required to identify the bacterial organism causing the infection. A “use additional code” note will normally be found at the infectious disease code, indicating a need for the organism code to be added as a secondary code.”

Therefore, N39.0 should be sequenced first, followed by B96.20.

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

It is essential that all general and chapter-specific coding guidelines be reviewed before making your final code selection. Review all the Inclusion terms, Includes, Use additional, Excludes1 and Excludes2 notes.

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

  • https://www.cdc.gov/antibiotic-use/community/for-patients/common-illnesses/uti.html
  • https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7260639/
  • https://www.ncbi.nlm.nih.gov/books/NBK537282/
  • https://www.niddk.nih.gov/health-information/urologic-diseases/bladder-infection-uti-in-adults
  • https://www.auanet.org//education/auauniversity/for-medical-students/medical-students-curriculum/medical-student-curriculum/adult-uti
  • https://www.mayoclinic.org/diseases-conditions/urinary-tract-infection/symptoms-causes/syc-20353447


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