"Every day, a person's kidneys process about 200 quarts of blood to sift out about 2 quarts of waste products and extra water. The wastes and extra water become urine, which flows to the bladder through tubes called ureters," according to the National Kidney and Urological Diseases and Information Clearinghouse. All three parts of a urinalysis test, including reference ranges, are reported to the clinician for interpretation of the health of the kidneys, ureters and bladder.
Urinalysis Visual
When a sample of urine arrives in the laboratory, the first part of the urinalysis begins. A lab technician trained in examining urine will note the color and clarity of the specimen. Urine normally appears medium yellow in color, and clear with no visible debris. Dark amber urine indicates dehydration and concentration of the specimen, or the presence of bilirubin from liver abnormalities. Red, pink or brown urine may be caused by fresh or hemolysed blood. Dark orange urine indicates the presence of the drug pyridium, which is used to treat urinary tract infections. Other colors are possible, and are caused by drugs or dyes given to the patient. Visible debris caused by material being shed or eliminated by the kidneys and bladder can be seen suspended in the urine if present. Contamination from the vagina frequently causes visible debris.
Urinalysis Chemical
A urine dip stick that is coated with chemically reactive squares is dipped into the urine to analyze specific gravity, or concentration, as well as the presence of white blood cells and red blood cells. Other squares on the stick detect chemical by-products of the body and indicate whether the chemicals are present in small, medium or large amounts. Chemicals secreted in the urine include bile, glucose, nitrates and protein, and the pH level is also checked. The pH level indicates whether the urine is acidic, neutral or alkaline. Bacteria secrete nitrates, indicating a urinary tract infection. Glucose squares will detect too much sugar in the urine from diabetes or metabolic conditions. Medium to large amounts of bile or bilirubin detected by chemical reactions may indicate an abnormal liver or digestive condition.
Urinalysis Microscopic
Part of the urine specimen is poured into a conical tube and then centrifuged to pack the visible debris into a button. After pouring off the top urine layer, the sediment is re-suspended and inspected using a slide, cover slip and microscope. Microscopic debris identified by a trained laboratory worker can include cells, bacteria, mucus, parasites, crystals and formed elements eliminated by the kidneys. Small amounts of microscopic debris may be normal. Parasites found in urine are never normal. Large amounts of bacteria indicate a urinary tract infection. Bacteria are usually accompanied by increased amounts of white blood cells, which can be seen under the microscope.
