urinalysis urinalysis urinalysis, a portmanteau of the words urine and analysis, is a panel of medical tests that includes physical (macroscopic) examination of the urine, chemical evaluation using urine test strips, and microscopic examination. macroscopic examination targets parameters such as color, clarity, odor, and specific gravity; urine test strips measure chemical properties such as ph, glucose concentration, and protein levels; and microscopy is performed to identify elements such as cells, urinary casts, crystals, and organisms. this article is about the routine physical, chemical, and microscopic examination of urine. for other tests performed on urine, see urine test. urinalysisprocedures in urinalysis. left: a urine test strip is immersed into the sample. top right: urine is about to be examined under a phase-contrast microscope using a neubauer counting chamber. bottom right: phase-contrast microscopic image showing many white blood cells in the urine (pyuria).meshd016482other codesloinc codes for urinalysis panelsmedlineplus003579 background structure of the kidney and nephron urine is produced by the filtration of blood in the kidneys. the formation of urine takes place in microscopic structures called nephrons, about one million of which are found in a normal human kidney. blood enters the kidney though the renal artery and flows through the kidney's vasculature into the glomerulus, a tangled knot of capillaries surrounded by bowman's capsule. the glomerulus and bowman's capsule together form the renal corpuscle. a healthy glomerulus allows many solutes in the blood to pass through, but does not permit the passage of cells or high-molecular weight substances such as most proteins. the filtrate from the glomerulus enters the capsule and proceeds to the renal tubules, which reabsorb water and solutes from the filtrate into the circulation and secrete substances from the blood into the urine in order to maintain homeostasis. the first destination is the proximal convoluted tubule. the filtrate proceeds into the loop of henle, then flows through the distal convoluted tubule to the collecting duct. the collecting ducts ultimately drain into the renal calyces, which lead to the renal pelvis and the ureter. urine flows through the ureters into the bladder and exits the body through the urethra. besides excreting waste products, the process of urine formation helps to maintain fluid, electrolyte and acid-base balance in the body. the composition of urine reflects not only the functioning of the kidneys, but numerous other aspects of the body's regulatory processes. the ease with which a urine sample can be obtained makes it a practical choice for diagnostic testing. medical uses urinalysis involves assessment of the physical properties of urine, such as color and clarity; chemical analysis using urine test strips; and microscopic examination. test strips contain pads impregnated with chemical compounds that change color when they interact with specific elements in the sample, such as glucose, protein and blood, and microscopic examination permits the counting and classification of solid elements of the urine, such as cells, crystals, and bacteria. urinalysis is one of the most commonly performed medical laboratory tests. it is frequently used to help diagnose urinary tract infections and to investigate other issues with the urinary system, such as incontinence. it may be used to screen for diseases as part of a medical assessment. the results can suggest the presence of conditions such as kidney disease, liver disease and diabetes. in emergency medicine urinalysis is used to investigate numerous symptoms, including abdominal and pelvic pain, fever, and confusion. during pregnancy, it may be performed to screen for protein in the urine (proteinuria), which can be a sign of pre-eclampsia, and bacteria in the urine, which is associated with pregnancy complications. the analysis of urine is invaluable in the diagnosis and management of kidney diseases. specimen collection samples for urinalysis are collected into a clean (preferably sterile) container. the sample can be collected at any time of the day, but the first urine of the morning is preferred because it is more concentrated. to prevent contamination, a "midstream clean-catch" technique is recommended, in which the genital area is cleaned before urinating and the sample is collected partway through the urination. samples can also be collected from a urinary catheter or by inserting a needle through the abdomen and into the bladder (suprapubic aspiration). in infants and young children, urine may be collected into a bag attached to the genital region, but this is associated with a high risk of contamination. if the sample is not tested promptly, inaccurate results can occur because bacteria in the urine will multiply and elements such as cells and casts will degrade. it is recommended that urinalysis is performed within two hours of sample collection if the urine is not refrigerated. macroscopic examination color and clarity