How UTIs Are Diagnosed

UTI diagnosis
© Verywell, 2018

Diagnosing urinary tract infections (UTIs) typically involves the analysis of a urine sample, but in some cases imaging tests may be used.

Every year, UTIs account for as many as 8.1 million visits to health care providers. While UTIs can cause a great deal of pain and discomfort, seeking a diagnosis is the first step in finding relief. What’s more, UTI diagnosis and subsequent treatment can protect you from potentially serious complications, such as permanent kidney damage.

At-Home Testing

A number of over-the-counter products may help you test for a UTI on your own, usually by holding a dipstick in your urine stream and then checking the testing strip for changes.

But while these home test kits are popular among people with recurring UTIs, they’re not nearly as reliable as the diagnostic tools used by medical professionals. Therefore, it’s important to see your doctor right away if you’re experiencing UTI symptoms such as pain or burning when you urinate, fever, and an urge to urinate frequently.

Labs and Tests

If you’re seeing your doctor to diagnose a possible UTI, you’ll most likely have to provide a urine sample.

To make sure the sample is sterile, urine is often collected according to a process called “the clean catch method.” You’ll be given an antiseptic cleansing pad to clean your genital area before providing the urine sample. As with all urine samples, your collection container should have markings to indicate the amount of urine required for analysis.

Unlike many other diagnostic tests (such as blood tests), there’s usually no need to fast or follow other special instructions in preparation.

Urine samples are used to perform the following types of diagnostic tests.

Urinalysis

Defined as the physical, chemical, and microscopic examination of urine, urinalysis entails checking the urine for infection-causing bacteria and other substances.

These substances may include nitrites, which can signal the presence of a UTI. While urine normally contains chemicals known as nitrates, those chemicals can turn into nitrites when bacteria enter your urinary tract.

During urinalysis, your health care provider will also look at the white blood cell count in your urine. A high white blood cell count in urine is often an indication of infection.

According to the U.S. Department of Health and Human Services, urinalysis can diagnose an infection most of the time.

Urine Culture

Also known as a “bacteria culture test,” a urine culture is frequently used as a follow-up to urinalysis. With the help of a urine culture, your health care provider can identify the specific bacteria causing your UTI and, in turn, select the most effective antibiotic to use in treatment.

A urine culture involves taking part of your urine sample and placing it in a special environment in the lab to promote cell growth. In the presence of infection, the bacteria causing the infection will soon begin to multiply. Although results are usually available within a few days, certain slow-growing bacteria may take several days or longer to analyze.

Imaging

If your UTI symptoms fail to subside, even after treatment, further testing can determine if there are other problems in your urinary tract.

This further testing includes the use of imaging techniques, which provide pictures of your urinary tract. Such tests may also be used to identify urinary tract abnormalities in people who frequently suffer from UTIs.

Imaging tests used to diagnose urinary tract issues include ultrasounds, computerized tomography (CT) scans, and magnetic resonance imaging (MRI). In the diagnosis of frequent urinary tract infections (or underlying medical problems in people with UTIs), doctors sometimes perform an imaging test known as ​a cystoscopy.

Cystoscopy

Performed by urologists (medical specialists who focus on the urinary tract), cystoscopy uses a long, thin instrument to look inside your urethra and bladder.

This instrument is called a cystoscope and features an eyepiece at one end, a tube in the middle, and a tiny lens and light at the opposite end of the tube. The cystoscope provides detailed images of the lining of the urethra and bladder, which are both part of the urinary tract.

Although you might not need to perform any special preparation for your cystoscopy, your doctor may ask you to drink plenty of liquid prior to the test. In some cases, you may need to temporarily discontinue use of certain medications (such as blood thinners).

When used to diagnose a UTI, cystoscopy takes about 15 to 30 minutes. The test is typically provided during an office visit or in an outpatient center or hospital. To prevent discomfort, your urologist will apply an anesthetic gel around the urethral opening (or inject a local anesthetic into the urethra). For women, cystoscopy is performed with the patient lying on her back with her knees up and spread apart. Male patients can either lie on their back or assume a sitting position.

Once the anesthetic has taken effect, your urologist will gently insert the tip of the cystoscope into your urethra, then slowly glide it through the urethra and into the bladder. In order to obtain a clear view of the bladder wall, saline is used to fill and stretch the bladder. (It should be noted that this part of the procedure may cause some discomfort or the urge to urinate.) When your urologist has finished examining your urethra and bladder, he or she may remove the saline from your bladder, or ask you to empty your bladder by urinating.

After undergoing a cystoscopy, you may experience such issues as a mild burning feeling or discomfort in your bladder area or kidney area when urinating. Some patients also see small amounts of blood in their urine or feel the need urinate more frequently or urgently. If these problems persist for more than 24 hours, make sure to consult your doctor.

You should also seek medical attention if you experience symptoms like the inability to urinate despite the feeling of a full bladder, bright red urine or blood clots in the urine, severe discomfort, or fever.

Taking a warm bath or using over-the-counter pain relievers may help alleviate post-cystoscopy discomfort.

Differential Diagnosis

UTIs can trigger signs and symptoms similar to those associated with other issues affecting the urinary tract. The following conditions are commonly considered when you are being evaluated for a possible UTI:

Your doctor will be able to differentiate between these using the diagnostic tests described above.

Sources:

National Institute of Child Health and Human Development Information Resource Center. “How many women are affected or at risk for UTIs & UI?” December 2016.

National Institute of Diabetes and Digestive and Kidney Diseases. “Urinary Tract Imaging.” May 2012.

National Institute of Diabetes and Digestive and Kidney Diseases. “Cystoscopy & Ureteroscopy.” June 2015.

Urology Care Foundation. “What is a Urinary Tract Infection (UTI) in Adults?