Urinalysis involves testing the urine of a patient. Doctors look at the properties of the urine such as color, clarity and pH. They also evaluate the amount of protein, glucose, nitrite and other chemicals. All of these provide important clues as to the patient's well-being.
Several different techniques are available for performing urinalysis. Knowing how the urinalysis is performed and how the results are expressed helps to make sense of your lab reports.
Dipstick
The dipstick test involves dipping a piece of indicator paper into a urine sample provided by the patient. The advantage of this technique is that multiple tests are performed very cheaply. According to the University of Utah Medical School, a single indicator strip measures pH, specific density, protein, glucose, ketones, nitrite and leukocyte esterase. These values are reported as "neg," "trace," "+1," "+2," and so forth. Although this information is not very specific, it is a good first step in a diagnostic workup because other types of urinalysis can be used if these results are out of range.
Many papers, including one published in the December 2001 "Pediatric Nephrology" by B.S. Cho, point to the routine urinalysis of school children and workers in Japan and Korea. This practice is as common in those countries as vision and hearing tests are for U.S. schoolchildren.
Macroscopic Analysis
A lab tech performs macroscopic analysis by looking at the sample and evaluating the color and clarity of the specimen. Although the color of normal urine varies from light to deep amber, it should always be clear.
Urine may be cloudy if it contains excessive protein, red or white blood cells, or detritus known as "casts."
Microscopic Analysis
Another urinalysis technique involves examining the urine specimen under a microscope. The University of Utah Medical School explains that the urine specimen is centrifuged and almost all of the liquid known as the supernatant is poured off.
The material remaining in the bottom of the centrifuge tube is resuspended in the remaining supernatant and examined under a high-power light microscope. The lab tech searches for white cells, red blood cells, casts and epithelial cells. If such cells are found, the tech reports her findings by indicating how many cells per high-powered field are found. For example, a typical result on a lab report might read "RBCs - 3-5 HPF." This means that there were between three and five red blood cells found when examining the specimen under a high-powered light microscope.
