Examination of Urine for Normal Constituents
Urine is the excretory product of the body produced by the process of filtration, reabsorption, and tubular secretion. Urine can be collected and examined easily, and presence of certain substances in the urine may indicate the metabolic state of the body. The routine and microscopic examinations of urine are helpful in the diagnosis of several pathological conditions. A random sample is usually taken for routine clinical examination; however, first-morning urine is preferred for urinalysis and microscopic analysis, since it is generally more conc. Fresh or preserved urine samples are used for chemical and culture-based microbiological testing. The specimens that are unpreserved for more than 2 h or refrigerated for a long time may not be suitable for analysis due to potential bacterial overgrowth and invalidation of bacterial colony counts or errors in chemical urinalysis.