A urine test (urinalysis) uses a sample of urine to diagnose diseases of the urinary system and other body systems. Urinalysis may be ordered to check for early signs of a disease or disorder, or it may be used to monitor kidney or liver diseases as well as inflammatory illnesses resulting in pain, such as:

• Gout. One of the most painful forms of arthritis.
  
  
• Reiter’s syndrome. A form of reactive arthritis that involves inflammation of joints, the urethra and the lining of the eyes.
  
  
• Systemic lupus erythematosus (SLE). An autoimmune disease involving the skin, joints and internal organs.
  
  
• Scleroderma. An autoimmune connective-tissue disorder characterized by changes in the skin, blood vessels, skeletal muscles and internal organs.
  
  
• Urinary tract infections (UTIs). Bacterial infections in the urinary system are especially common in women.
  
  
• Prostatitis. An acute or chronic inflammation of the prostate gland. This cause of pelvic pain and sexual pain is a common condition in men.
  
  
• Orchitis (inflammation of a testicle) or epididymitis (inflammation of the epididymis, a spermatic duct). These sources of testicular and scrotal pain are often but not always caused by sexually transmitted diseases.
  
  
• Cancers. Urine tests can reveal tumors of the bladder, prostate, kidneys and urethra and a type of blood cancer called multiple myeloma.

Urine tests serve a number of purposes, such as:

• Checking levels of uric acid – the end product of the breakdown of nucleotides as a normal part of metabolism – to monitor treatment of gout.
  
  
• Monitoring for or detecting the presence of substances in urine that indicate kidney disease:
  
  
• • Blood (hematuria) to diagnose or monitor lupus nephritis (kidney disease that is a complication of lupus). Hematuria can also indicate tumors, prostate disorders or a lesion or stones in the urinary tract.
    
    
  • Proteins (microalbuminuria or proteinuria), a possible complication of scleroderma, lupus or diabetes. In addition, proteinuria can be due to preeclampsia, a complication of pregnancy that also involves high blood pressure.
    
    
  • Creatinine (a waste product of the metabolism of creatine, a component of muscle) to diagnose kidney damage.
    
    
• Assessing levels of minerals to help diagnose diseases. For example, elevated levels of calcium in urine can suggest certain types of cancer. Below-normal amounts of phosphate in urine can indicate osteomalacia (a painful condition characterized by weakened bones) or kidney diseases.
  
  
• Finding tumor markers. Several tumor markers, including an enzyme called telomerase, often can reveal bladder cancer. A recently discovered tumor marker called thymosin beta-15 can indicate prostate cancer.
  
  
• Revealing pregnancy. Home pregnancy tests can usually detect pregnancy about two weeks after conception.
  
  
• Indicating menopause. The U.S. Food and Drug Administration has approved a home urine test kit that measures follicle stimulating hormone (FSH) and may show that a woman is in or about to enter menopause.

Urine testing is a simple and easy method of detecting potentially serious conditions early. This allows for treatments that may delay or prevent the onset of more serious complications.

Samples of urine may be taken in several ways:

• Spot sample (also called dipstick method). A single urine sample.
  
  
• 24-hour urine sample. A collection of all urine for a 24-hour period.
  
  
• Overnight urine sample. A collection of all urine excreted between going to sleep at night and waking up in the morning.
  
  
• Timed urine sample. A collection of all urine voided in a specific period (e.g., four hours).

Spot samples provided in a physician’s office should be tested within 15 minutes of collection. Immediately after the sample is taken, the cup is labeled with the date and the patient’s name. Twenty-four-hour samples need to be refrigerated throughout the day and are tested once turned over to the physician’s office or lab. The 24-hour sample is the most accurate way of testing conditions such as microalbuminuria, but because of its inconvenience, a physician may recommend an overnight or timed sample instead.

Different urine tests may require different methods of analysis. Urinalysis may include:

• Visual examination. Tester visually examines the color and clearness of the urine sample. Blood may make the urine appear red or brown. An infection may cause the sample to appear cloudy.
  
  
• Test strip examination. Tester uses a chemically-coated test strip to measure the amount of certain substances in the urine including blood, glucose, creatinine, protein, pH, nitrite, ketones and bilirubin. The test strip is dipped into the urine sample. A chemically coated test pad on the strip will react with the urine and change color accordingly. The test pad is then compared to a color chart of possible results. Test times vary, but most test strips provide results in less than a minute.
  
  
• Microscopic examination. The tester examines a small amount of urine under a microscope. Cells, bacteria, casts (protein substances that can indicate kidney disorders), crystals and other matter are counted and reported as either the number observed or as estimates (e.g., few, moderate or many).
  
  
• Culture. When the presence of bacteria is suspected in the urine, a urine culture may be ordered. A sample of urine is streaked across the surface of one or more lab dishes (Petri dish). The sample is then placed in an incubator that keeps the urine at body temperature. Bacteria will be allowed to grow in the dish so the type of bacteria can be determined. If there is no growth on the dish at the end of 24 hours, the test is considered negative for infection. If yeast or bacteria are present, the organisms are identified and counted. Further testing is then conducted to determine which antibiotics are likely to be effective in treating the infection.