The urinalysis department, often paired with the chemistry department, is the area where urine is visually, chemically, and microscopically examined. Urine specimens are received in sterile cups.
The first step in urinalysis is the visual inspection of the urine specimen. The urine is examined for color and clarity. Normal, healthy urine varies from pale yellow (dilute) to amber (concentrate). Normal urine is clear at first and then becomes cloudy when allowed to sit. If the specimen is cloudy or turbid before it sits, the lack of clarity may be an indicator of infection. Unusual odors may also indicate infection.
The second step in urinalysis is the chemical examination. The chemical examination is performed by using a urine test strip, or dipstick. The strip contains up to 10 pads, each containing a specific chemical marker for various analytes including leukocytes, nitrites, urobilinogen, protein, pH, hemoglobin, specific gravity, ketones, bilirubin, and glucose. When the strip is dipped in the urine, the pads turn different colors. The colors are compared against a color scale on the bottle that indicates their quantitative values based on the lightness, darkness, and hue of the colors. This is performed by either a semi-automated analyzer or a trained professional.
The third step in urinalysis is the microscopic evaluation. If an abnormality is detected in the visual and/or chemical examination, then the urine will be microscopically reviewed for formed elements such as cells, casts, and crystals. For example, if leukocytes and nitrites are positive on the dipstick, then the specimen will undergo microscopic examination for the presence of bacteria and leukocytes.
8. Beckman Coulter. "AUTION MAX™ AX-4030 Fully Automated Urine Chemistry Analyzer." Beckman Coulter, https://www.beckmancoulter.com/en/products/urinalysis/aution-max-ax-4030. Accessed 10 November 2020.