Urinary tract infections (UTI) are one of the most common reasons for adults to seek primary medical care. As a result, it is essential that health professional are able to accurately diagnose the condition in order to provide the best medical treatment and avoid overuse of antibiotics for those that do not require it.

Studies have shown that UTI diagnosis made solely on the basis of clinical criteria has an error rate of approximately one in three cases. Diagnostic algorithms can help to reduce this error rate, but do not eliminate it entirely.

Presenting Signs and Symptoms

Initially, the patient reported signs and symptoms that may be indicative of a urinary tract infection are used to make the diagnosis. Signs that suggest a UTI may be present include:

• Frequent urination
• Passing small volumes of urine
• Pain on urination
• Discolored or cloudy urine
• Pungent urine
• Pain in lower abdominal region or back
• General feeling of being unwell.

However, these symptoms are not always specific to urinary tract infection and further testing is usually required to confirm the diagnosis.

High-Risk Populations

Awareness of groups of people that are at a higher risk of contracting a urinary tract infection can help in the diagnostic process.

People more likely to get a UTI include:

• Women
• Sexually active women
• Pregnant women
• Use of diaphragm birth control
• Menopausal women
• Abnormalities or blockages in urinary tract
• Suppressed immune system
• Catheter use

This is not to say other individuals should not be considered, as anyone can get a UTI, but it can help with diagnosis to recognize individuals at high-risk.

Urine Tests

Urinalysis is an easy test that a primary healthcare professional can use to get an immediate indication of the likelihood of a urinary tract infection. It involves a urine sample, which is analyzed for color, smell and with simple chemical tests to detect the presence of bacteria.

In some cases, a urine culture may be sent to a laboratory to identify the specific bacteria that are responsible for causing the infection. This is particularly useful in severe infections that are suspected to be caused by resistant bacteria, such as those acquired in a hospital setting.

Other Diagnostic Tests

Other diagnostic tests are often utilized when the patient is not responsive to treatment to investigate the true cause of the symptoms.

• Ultrasound imaging is a non-invasive test that can aid in the detection of any obstruction in urine flow such as from kidney stones or kidney abscesses.

• X-ray imaging can identify structural abnormalities of the urinary tract, such as narrowing of the urethra and incomplete bladder emptying.

• Cystoscopy is occasionally used to investigate structural abnormalities or interstitial cystitis that may not be clear in X-ray images.

• Computed tomography (CT) scans can detect obstruction of urinary flow, such as kidney stones.

• Blood tests can identify the presence of infection in the bloodstream and may be used when a patient presents with severe symptoms.

Differential Diagnosis

Many patients that are suspected to have a urinary tract infection are, in fact, affected by another condition. In order to avoid misdiagnosis and unsuitable treatment, differential diagnosis should eliminate other possible conditions.

Vaginitis or thrush is commonly confused with a UTI as it presents with similar symptoms, such as frequent urination. However, vaginitis is associated with other characteristic symptoms, such as itching and cream cheese-like discharge.

Sexually transmitted diseases (STD) can also cause symptoms of pain on urination. This may be considered when the urine culture does not show signs of bacterial growth.

References

• http://www.nhs.uk/Conditions/Urinary-tract-infection-adults/Pages/Diagnosis.aspx
• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2883276/
• http://cid.oxfordjournals.org/content/38/8/1150.full
• http://www.nytimes.com/health/guides/disease/urinary-tract-infection/diagnosis.html
• http://www.mayoclinic.org/diseases-conditions/urinary-tract-infection/basics/risk-factors/con-20037892

Further Reading

• All Urinary Tract Infection Content
• What is a Urinary Tract Infection?
• Urinary Tract Infection Symptoms
• Urinary Tract Infection Treatment
• Urinary Tract Infection Prevention

Written by

Yolanda Smith

Yolanda graduated with a Bachelor of Pharmacy at the University of South Australia and has experience working in both Australia and Italy. She is passionate about how medicine, diet and lifestyle affect our health and enjoys helping people understand this. In her spare time she loves to explore the world and learn about new cultures and languages.