A urinalysis is a group of tests that detect and semi-quantitatively measure various compounds that are eliminated in the urine, including the byproducts of normal and abnormal metabolism as well as cells, including bacteria, and cellular fragments. Urine is produced by the kidneys, located on either side of the spine at the bottom of the ribcage. The kidneys filter wastes and metabolic byproducts out of the blood, help regulate the amount of water in the body, and conserve proteins, electrolytes, and other compounds that the body can reuse. Anything that is not needed is excreted in the urine and travels from the kidneys to the bladder, through the urethra, and out of the body. Urine is generally yellow and relatively clear, but every time someone urinates, the color, quantity, concentration, and content of the urine will be slightly different because of varying constituents.
Many disorders can be diagnosed in their early stages by detecting abnormalities in the urine. These include increased concentrations of constituents that are not usually found in significant quantities in the urine, such as: glucose, protein, bilirubin, red blood cells, white blood cells, crystals, and bacteria. They may be present because there are elevated concentrations of the substance in the blood and the body is trying to decrease blood levels by “dumping” them in the urine, because kidney disease has made the kidneys less effective at filtering, or in the case of bacteria, due to an infection.
A complete urinalysis consists of three distinct testing phases:
- physical examination, which evaluates the urine’s color, clarity, and concentration;
- chemical examination, which tests chemically for 9 substances that provide valuable information about health and disease; and
- microscopic examination, which identifies and counts the type of cells, casts, crystals, and other components (bacteria, mucus ) that can be present in urine.
Usually, a routine urinalysis consists of the physical and the chemical examinations. These two phases can be completed in just a few minutes in the laboratory . A microscopic examination is then performed if there is an abnormal finding on the physical or chemical examination, or if the doctor specifically orders it.
How is the sample collected for testing?
Urine for a urinalysis can be collected at any time. Because of the potential to contaminate urine with bacteria and cells from the surrounding skin during collection (particularly in women), it is important to first clean the genitalia. Women should spread the labia of the vagina and clean from front to back; men should wipe the tip of the penis. As you start to urinate, let some urine fall into the toilet, then collect one to two ounces of urine in the container provided, then void the rest into the toilet. This type of collection is called a midstream collection or a clean catch.
If you have additional questions, or you would like to schedule a test, please contact us. Calls are always confidential.