If you have symptoms of a urinary tract infection (UTI), your initial evaluation by a doctor will probably include:

• A medical history and physical exam.
• Urinalysis.

Your doctor may order a urine culture to confirm the diagnosis of a suspected UTI. But if your symptoms, medical history, and urinalysis make the presence of an uncomplicated urinary tract infection likely, your doctor may have you begin treatment with antibiotics without waiting for the results of a urine culture.

A doctor may order a urine culture:

• For women with unusual UTI symptoms, such as symptoms that last longer than 7 days, or symptoms of a kidney infection (pyelonephritis).
• For men before and after treatment for a UTI.
• For anyone older than 65 with UTI symptoms.
• If you have diabetes, an impaired immune system, or structural problems in your urinary tract.
• If your UTI symptoms return after 3 days of treatment. A urine culture can identify what type of bacteria is causing the infection, so that the most effective antibiotic for that bacteria can be used.
• After treatment for a UTI in people who have kidney infections (pyelonephritis), to make sure the infection is cured.
• To screen young girls for asymptomatic bacteriuria.

If you are pregnant, your doctor may order a urine culture:

• If you have UTI symptoms.
• After treatment for a UTI.
• To screen for asymptomatic bacteriuria.

Tests used less frequently

If the infection does not respond to treatment with antibiotics or recurs rapidly, if the infection may be complicated by other factors, or, in some cases, if the kidneys are infected, your doctor may order other tests to:

• Determine the cause of recurrent or chronic infections.
• Check for other kidney problems.
• Diagnose structural problems of the urinary tract that might make you more likely to get UTIs.
• Determine whether the infection is caused by unusual bacteria.
• Determine whether you have an impaired immune system.

Tests used for these purposes may include:

• Abdominal ultrasound, which uses reflected sound waves to produce a picture of the upper abdomen.
• Pelvic ultrasound, which uses reflected sound waves to produce a picture of the lower abdomen.
• Voiding cystourethrogram, which is an X-ray test that takes pictures of your bladder and urethra while you are urinating.
• Cystometry, which measures your bladder's ability to hold in and push out water or gas.
• Cystoscopy, which allows your doctor to look at the interior lining of the bladder and the urethra.
• Intravenous pyelogram (IVP), an X-ray test that provides pictures of the size, shape, and position of the kidneys, bladder, ureters, and urethra.
• Spiral (helical) CT urogram, a high-speed (about 90 seconds) scanner that provides detailed pictures of the area scanned.

Early Detection

Experts disagree about the value and cost-effectiveness of screening people who are at high risk for urinary tract infections. Factors that increase the risk for UTIs include previous UTIs, using condoms coated with spermicide, and prostate problems.

All pregnant women should receive screening for asymptomatic bacteriuria.