Urinalysis is an indispensable part of clinical pathology. It may uncover disease anywhere in the urinary tract. Also, it may afford a semiquantitative estimate of renal function and furnish clues to the etiology of dysfunction. Certain systemic diseases may produce quantitative or qualitative alterations of urine constituents or excretion of abnormal substances, quite apart from direct effects on the kidneys. Conversely, urinary tract disease may produce striking systemic symptoms.

The standard urinalysis test panel includes specimen appearance, pH, specific gravity, protein semiquantitation, presence or absence of glucose and ketones, and microscopic examination of the centrifuged urinary sediment for white blood cells (WBCs), red blood cells (RBCs), and other abnormalities. (Table 12-1). These tests (not including microscopic examination) can be performed separately or together in various combinations on dipsticks available from several manufacturers. Some manufacturers have added one or more of the following tests to their dipsticks: hemoglobin, bile (conjugated bilirubin), urobilinogen, nitrite, leukocyte esterase, and specificgravity. Instruments that process and read the dipsticks are now available, thereby improving accuracy by eliminating some of the subjective element that is inherent in color changes read by human eye.

Most important conditions screened for in basic urinalysis

Table 12-1 Most important conditions screened for in basic urinalysis