Urine and your health

A kit for analyzing urine samples, including a collection vial with a screw-on cap, test strips, and a color-coded guide for interpreting the results.

One of the simplest diagnostic tests available can tell you a great deal about your health. All you need to do is share a few ounces of urine.

“A urine test, also known as a urinalysis, can open up a window on what’s happening in the body,” says urologist Dr. Francis McGovern with Harvard-affiliated Massachusetts General Hospital. “The results can provide a lead toward diagnosing diabetes, liver disease, or kidney disorders.”

What does a urine test show?

The kidneys produce urine to remove excess fluid and waste products from the body. Urine also contains various chemicals, minerals, toxins, bacteria, and red and white blood cells. A urine test can reveal the presence and amounts of these substances, which can provide clues to specific conditions.

A urine test also can be used to help doctors diagnose an underlying problem related to specific symptoms, such as blood in the urine, abdominal pain, back pain, or frequent or painful urination. If you have an ailment such as kidney disease or a urinary tract infection (UTI), regular urine tests help your doctor monitor your condition and treatment.

How a urinalysis works

For a urinalysis, you provide a urine sample by peeing into a plastic cup or container. To get the best results, you must provide a “clean catch” sample, which means it’s not contaminated by skin cells or bacteria from outside the body. First, cleanse the area around your urethra (where urine exits) with water (no soap) or use an antiseptic wipe. Since the initial flow of urine may have bacteria from around the urethra’s opening, urinate into the toilet for a moment and then use the cup to collect the middle portion of the urine stream.

Understanding urinalysis results

The urine sample is analyzed in three ways: visual exam, chemical exam, and microscopic exam.

Visual exam. A visual exam checks the color and clarity. Normal urine has a pale yellow color. Dark yellow suggests a person is dehydrated. Brown or cola-colored urine tends to occur in people with liver disease or blockage in the bile duct.

A reddish color might come from blood in the urine. This can suggest kidney stones or an enlarged prostate, or something more serious like cancer of the urinary tract or kidney. In some cases, red urine occurs after a person eats large amounts of beets. “If you notice your urine is reddish and you haven’t recently eaten beets, or if you notice blood, contact your doctor to get a urinalysis and evaluation immediately,” says Dr. McGovern.

Clear urine means a person is well hydrated. Cloudy urine could be a sign of a urinary tract infection (UTI), diabetes, sexually transmitted disease, or kidney disease. “If the urine appears foamy, this could indicate excess protein and be a sign of kidney dysfunction,” says Dr. McGovern.

Chemical exam. After the visual exam, the urine’s chemical composition is checked using a dipstick, a plastic strip with a row of chemical pads on it. The dipstick is placed in the urine, and the patches change color if certain substances are present or if levels are above or below normal. Here’s what the dipstick test routinely checks.

Protein: High levels can indicate possible kidney disease.
Sugar (glucose): Detection means you need blood testing for diabetes.
Ketones: They get excreted by the kidneys when the body burns fat for calories, which can happen when people fast, don’t eat enough carbohydrates, or have diabetes.
Blood (hemoglobin): High levels most often indicate the presence of full or fragmented red blood cells.
Bilirubin and urobilinogen: Either or both can be present when there is liver disease, bile duct obstruction, or red cell breakdown.
White blood cells: Their presence indicates inflammation in the bladder or kidneys, most often caused by infection.
Nitrite: Nitrite, a chemical produced by most bacteria, suggests a bacterial infection.
Specific gravity: This is a measure of your hydration status and the kidneys’ ability to regulate fluids. Low specific gravity can suggest excessive fluid intake or kidney damage. High specific gravity is a sign of dehydration.
Acidity (pH value): Normal urine pH value ranges from about 5 to 7. Urine pH below or above the normal range can increase risk of different types of kidney stones.

Microscopic exam. If the dipstick test produces abnormal results, the urine is analyzed under a microscope. Higher-than-normal levels of red blood cells may indicate an issue with the kidney, bladder, prostate, or urinary tract, or an underlying medical condition. Higher amounts of white blood cells might mean there’s an inflammation, usually due to an infection somewhere in the urinary tract.

A microscopic exam can also reveal other indicators of potential problems. Here are some examples:

Crystals: Certain types are a sign of kidney stones.
Bacteria, yeast, or parasites: These are signs of infection, such as a UTI, yeast infection, or sexually transmitted infection.
Urinary casts: Casts are tiny, tubelike particles made from red blood cells, white blood cells, or proteins released from the kidney into the urine. “The type of cast may help us diagnose a kidney illness,” says Dr. McGovern.

A quick and affordable tool for guiding next steps

A urine dipstick provides a simple, quick, and inexpensive way to help narrow down a diagnosis for many symptoms. Depending on the results, your doctor may immediately do an in-office urine microscopic exam or send the sample to the laboratory. Even a completely normal urine test offers key information to help direct other testing you may or may not need.