Urinalysis Components

Urinalysis

Components

• Protein: a small amount of filtered plasma proteins is normal, but more than 150 mg/day is considered proteinuria.
• Glucose: normal renal threshold is 160-180 mg/dl, and significant amounts in the urine is called glycosuria.
• Bilirubin: a highly pigmented compound that is a by-product of hemoglobin degradation, and its presence in the urine is an early indication of liver disease.
• Ketones: products of incomplete fat metabolism, appearing in the urine when there is a defect in carbohydrate metabolism.
• Nitrite: many bacteria that are urinary tract pathogens reduce nitrate to nitrite, and a positive nitrite test indicates their presence.

Microscopic Urinalysis

• Requires a light microscope to detect cells, debris, bacteria, and crystals.
• Hematuria: the presence of abnormal numbers of red blood cells, which can be due to glomerular damage, kidney trauma, urinary tract stones, or upper and lower urinary tract infections.

Background

• The urinary system consists of the kidneys, ureters, bladder, and urethra.
• The purpose of the urinary system is to eliminate waste, regulate blood volume and blood pressure, control levels of electrolytes and metabolites, and regulate blood pH.
• Average urine production in adult humans is about 1-2 liters per day, depending on state of hydration, activity level, environmental factors, weight, and individual health.
• Polyuria: a condition of excessive urine production (>2.5 L/day).
• Oliguria: a condition of insufficient urine production, which requires medical attention.