A urinalysis is a relatively routine medical procedure used to diagnose medical conditions, monitor health, and monitor existing conditions, including diabetes and kidney or liver disease. Because urine for the test needs to be fresh and uncontaminated, samples are usually collected at a physician's office. The collection route, however, is entirely non-invasive, as samples are eliminated through normal urination. The urine is then tested for a variety of substances, and the presence, absence or concentration of which provide indicators of health status.
Acid
One of the substances tested for in a standard urinalysis is acid, the concentration of which is often referred to as the urine's pH. Normal urine can be slightly acidic or slightly basic, which is the chemical opposite of acidity. According to the National Institutes of Health (NIH), urine should have a pH value between around 4.6 and 8; values outside this range are considered abnormal and can indicate a variety of medical conditions.
Protein and Sugar
Normal urine should contain very low levels of protein and sugar, if any at all, as these substances are generally filtered out of the urine by the kidneys. The Mayo Clinic notes that the presence of protein can indicate kidney disease, while sugar in the urine is typically a sign of diabetes. In fact, the proper name for diabetes is "diabetes mellitus," which is Greek for a condition producing large amounts of sweet urine.
Ketone Bodies
When cells are sugar-starved, they feed on breakdown products of fats which are called ketone bodies. These compounds, which are chemically related to the acetone in nail polish remover, indicate cellular starvation such as that resulting from diabetes. If ketone bodies appear in the urine, whether or not sugar is present, they are a sign of potential diabetes.
Blood Cells and Products
Blood cells and blood cell breakdown products should not normally be found in urine. Red blood cells, which are responsible for carrying oxygen from the lungs to the tissues, can indicate kidney infection, bladder infection, or kidney stones if present in urine, according to the Mayo Clinic. While white blood cells, which fight bacteria, are classically associated with infection and indicate urinary infection if found in the urine, red blood cells are associated with active infection because they indicate that the tissue of the urinary tract is inflamed and bleeding. A chemical called bilirubin is also an indicator of abnormal function, and standard urinalysis tests for this compound as well. Bilirubin is produced when the body breaks down red blood cells, and should not normally be found in large concentrations in the urine. High bilirubin concentrations indicate the potential for liver disease.
