Week 7: Intro to UA Urinalysis Renal anatomy and physiology Nephron anatomy Urine collection and preservation Physical properties of urine Color Appearance Specific gravity Volume Odor Foam

Urinalysis One of the oldest “lab” procedure Diabetes mellitus vs diabetes insipidus Examination of urine samples Physical properties Chemical components Microscopic sediments

Renal Anatomy Kidneys Renal artery and vein Medulla Cortex Calyx Ureter Bladder Urethra Adrenal glands

Nephron Functional unit of kidneys About one million per kidney Concentrate urine Filter blood Excrete waste products

Nephron Anatomy Afferent and efferent arterioles Glomerulus Bowman’s capsule Proximal convoluted tubules Loop of Henle Distal convoluted tubules Collecting duct

Nephron Function Ultrafiltration of blood 180 L/day of blood filtered >80% reabsorbed Antidiuretic hormone cause another 20% absorption 1-2 L/day urinary output Reabsorption of minerals and nutrients Active secretion of waste

Antidiuretic Hormone ADH Also called vasopressin Made in hypothalamus and secreted from posterior pituitary Increases porosity in distal tubule and collecting duct Lack of ADH result in d. insipidus Unable to concentrate urine (isosthenuria): constant specific gravity at 1.010

Normal Urine Contains… Urea from ammonia and CO 2 Uric acid from DNA metabolism Creatinine from muscle Electrolytes

Urine Collection Random 12 hour or 24 hour timed First morning void Clean catch Mid-stream Fasting Postprandial Urethral catheter Suprapubic aspiration

Decomposition of Urine Bacterial growth Ammonia or acid formation Change in pH Ketone evaporate Urobilinogen oxidized Bilirubin degradation with light Crystals Cells and casts lyse Change in color Alkaptonuria Change in specific gravity

Urine Preservation Refrigeration up to 8 hours Thymol to prevent bacterial growth Formalin to preserve cells Acid or base to preserve compounds

More Terms to Study Polyuria Oliguria Anuria Dysuria Hematuria Glycosuria Proteinuria Bacteriuria Cylindruia Hemoglobinuria

Color Normal: shade of yellow (straw to amber) Urochrome, uroerythrin Yellow due to bile in jaundice Red due to Hb or myoglobin Black in alkaptonuria after light exposure Other color due to medication

Appearance Normal: clear to slightly hazy Cloudy to turbid due to microscopic sediments White and red cells Bacteria and yeast Crystals

Specific Gravity Normal: (wider range with random collection) Urinometer: true reading of specific gravity Refractometer: use light refraction by dissolved substances Reagent strip: ionic concentration Osmometer: most accurate measurement of total dissolved substance

Refractometer vs Dipstix SG Refractometer measures dissolved substances Each gram of glucose raises SG by Each gram of protein raises SG by Correction gives more accurate measure of kidneys’ concentration ability Reagent strip measures ionic concentration Urinary waste will ionize so good measure of kidneys’ ability to concentrate Non-ionizing substances: glucose, protein, IVP

Other Information… Volume: ,600 mL per day For timed collection only Foam: white Yellow due to bile in hepatitis Excessive due to proteinuria

Other Information… Odor: faintly aromatic Foul due to bacterial growth Fruity due to ketones Maple Syrup Urine Disease Other due to food or medication