Urinalysis and other Body Fluids - 01 Intro to Urinalysis

ANALYSIS OF URINE AND OTHER BODY FLUIDS KIDNEY FUNCTIONS INTRODUCTION TO URINALYSIS 1. 2. OUTLINE • • • • • • • Interpretation of The Urinalysis (Video) Kidney Functions Nephron Urine Formation Factors that Influence Glomerular Filtration Tubular Reabsorption Mechanisms Tubular Secretion • • • • • • • • Urine composition Urine Volume Specimen Collection Specimen Integrity Specimen Preservation Changes in Unpreserved Urine Types of Specimen Discoverer/Persons who Contributed to the Urine Study 3. INTRODUCTION TO URINALYSIS 4. INTERPRETATION OF THE URINALYSIS (VIDEO) • Urinalysis (UA) o Commonly ordered panel of tests on a urine sample which can evaluate Kidney failure Acid-base disorders UTI Volume status Kidney/urinal stones Rhabdomyolysis GU malignancy Response to alkalinization therapy o Information can be divided into ▪ Gross inspection • Color • Turbidity ▪ Dipstick • Reagent strip - changes in color molecules Sp. Gravity leukocyte esterase pH nitrites glucose ketones heme bilirubin/urobilinogen protein ▪ Microscopy • WBCs • RBCs • Bacteria • Crystals • Casts o Urine Color ▪ Rough guide on hydration ▪ Influenced by medical conditions, medications, and ingested food ▪ Red Urine - bleeding, porphyria, factitious disorder ▪ Orange - hyperbilirubinemia ▪ Brown/black - concentrated red/orange ▪ Green - UTI secondary to pseudomonas ▪ Purple - UTI, infected urinary catheters ▪ White - hypercalciuria, phosphaturia, chyluria, o Urine Turbidity ▪ Turbid - UTI or precipitated crystals ▪ Not a specific finding for ither of these conditions 5. 6. removes metabolic waste from the blood in the form of urine retains substances necessary for the normal function of the body like CHON, amino acid, glucose, electrolytes and H2O o reabsorbs for homeostasis o glucose - macromolecule (naturally impermeable in kidney) ▪ glucose renal threshold - 180 mg/dL (excess will be mixed in urine) ▪ high glucose - can damage kidney o amino acids/protein - reabsorbed ▪ protein in urine can be physiologically normal in isolated cases ▪ constant proteinuria - can result in kidney failure regulates the H2O and electrolyte balance o retains or releases water depending on hydration level regulates the acid and base balance o maintains certain pH o blood - 7.35 - 7.45 o eliminates excess or reabsorbs H+ or OHinvolved in hormone synthesis such as erythropoietin and renin o specialized hormones o erythropoietin - stimulate blood forming organs to produce RBCs; injected to anemic o renin - regulates acid and base balance; has compensatory mechanism involved in catabolism of hormone insulin, glucagon and aldosterone NEPHRON • • Functional unit of the kidney Two Main Parts: o Glomerulus/Glomeruli ▪ Filters the blood o Renal tubules ▪ Proximal Convoluted Tubule - reabsorption ▪ Descending Loop ▪ Ascending Loop ▪ Distal Convoluted Tubule - reabsorbs molecules ▪ Collecting Tube/duct - connected to ureter URINE FORMATION URINE VOLUME Active Transport Proximal convoluted tubules • • • • • glucose amino acids salts sodium medications • • Passive Transport H2O urea Descending limb • H2O of loop of Henle Ascending limb • chloride • sodium of loop of Henle • urea Distal convoluted • sodium, • potassium tubule hydrogen ion Collecting duct • H2O H2O reabsorption controlled by presence & absence of ADH • ↑ ADH = ↓ urine volume = ↓ body hydration • ↓ ADH = ↑ urine volume = ↑ body hydration • • • • • • • Urea - converted ammonia FACTORS THAT INFLUENCE GLOMERULAR FILTRATION • • • cellular structure of capillary walls and bowman’s capsule o 1 - 1.5 million nephrons per kidney hydrostatic and oncotic pressure o influenced by presence of molecules in blood feedback mechanisms of RAA system o RAA - Renin-Angiotensin-Angiotensin-Aldosterone • • TUBULAR REABSORPTION MECHANISMS • • • Active - movement of substances across the cell membrane into bloodstream by electrochemical energy combined with a carrier protein in membrane of tubular cell o glucose, a.a., salts o chloride o sodium Passive – movement of molecules across a membrane by diffusion; high concentration to low concentration o water o urea o sodium Renal Threshold – plasma concentration at which active transport stops o Glucose - 180 mg/dL (excess will spill out in urine) TUBULAR SECRETION • • • SPECIMEN COLLECTION • • • elimination of waste products not filtered acid base balance through secretion of H+ ions URINE COMPOSITION • • 97-98% - water (95% book) 1-3% - electrolytes and other molecules (5% book) o Organic - indicators of kidney damage ▪ Urea (Blood Urea Nitrogen) ▪ creatinine - kidney damage ▪ uric acid - gouty arthritis o Inorganic - electrolytes ▪ chloride (Cl) ▪ sodium (Na) ▪ potassium (K) Urine Volume - 600-2000 mL/day or 1200-500 mL/day Night urine o not > 400 mL o kidneys excrete 2 to 3 times in day than in night Nocturia - > 500 mL at night Oliguria o < 400 mL/day (adult) o < 1 mL kg/hr (infant) o < 0.5 mL kg/hr (children) Anuria o near complete suppression of urine formation o total stoppage of urination Polyuria o increase urination o artificially induced by: ▪ caffeine ▪ alcohol ▪ thiazides o IV fluids o increase salt and protein intake o indication of diabetes ▪ 3Ps of diabetes (polyphagia, polydipsia, polyuria) Increase urine excretion (Pathologic) o Defective hormonal regulation of volume homeostasis o Defective renal salt/water absorption o Osmotic diuresis Decrease urine excretion (Pathologic) o Renal ischemia o Hemolytic transfusion reaction o Renal disease o Excessive H2O loss (vomiting, diarrhea, perspiration and severe burn Factors that influence urine volume o Fluid intake o Fluid loss from non-renal sources o Variation in the secretion of ADH o Necessity to excrete increased amount of dissolved solids such as glucose and salt ▪ Salt attracts water clean, dry, leak proof disposable container 50 mL recommended capacity (use 10-15 mL) reject specimens with: o no label o nonmatching labels and requisition forms o contaminated with feces or toilet paper o containers with contaminated exteriors o insufficient quantity o improperly transported SPECIMEN INTEGRITY • • delivered to lab within 2 hours immediately process to prevent bacteria from consuming urea converting it into ammonia SPECIMEN PRESERVATION • • • • • • • • • Qualities of ideal preservation: o bactericidal action o inhibit urease o preserve formed elements in the sediment Refrigeration - 2-8°C o Decreases bacterial growth and metabolism o Preserves crystals Thymol o Preserve glucose and sediment well o Interferes with acid precipitation of CHON Boric Acid o Preserve CHON and sediments well o Precipitates crystals if use in huge amount Formalin o Excellent sediment preservative o Acts as reducing agent Toluene - Floats on the surface of specimens Sodium fluoride - Good for drug analysis Saccomanno’s fixative - for cytology Urine collection tubes CHANGES IN UNPRESERVED URINE • • • • • • • • • • • color - metabolite reduction or oxidation clarity - bacterial growth and ppt of amorphous material odor - bacterial multiplication pH - breakdown of urea to ammonia glucose - can be eaten by bacteria ketones - byproduct of fat metabolism bilirubin - byproduct of Hgb breakdown urobilinogen - byproduct of bilirubin breakdown nitrite - converted by nitrate-reducing bacteria RBC, WBC and cast o WBC - sign of UTI o Casts - presence of bleeding bacteria - multiplication of bacteria TYPES OF SPECIMEN • • • • • • • • • Random 1st AM specimen o specimen of choice for routing U/A Fasting 2hr post-prandial - after eating Glucose tolerance specimen - us 24-hr / timed specimen o use for quantitative urine studies o begins and ends with empty bladder o if two containers, check for completeness of 24-hr collection ▪ Creatinine ▪ 4-aminobenzoic acid o First morning (day 1) - thrown o Second morning - start of collection, then refrigerate o First morning (day 2) - last collected Catheterized o measure function of individual kidney Midstream clean catch o safer less traumatic than catheterized Suprapubic aspiration o for cytologic exam o for culture • • • • • 3 glass collection – prostatic infection o 1st – first urine passed o 2nd – midstream portion o 3rd – prostate massage, remaining urine Pediatric specimen o soft clear plastic bags with adhesive (wee bag) 12-hr urine specimen 2PM to 4PM urine specimen Drug specimen collection o 30 to 45 mL o urine temperature must be taken within 4 minutes from the time of collection (32.5 to 37.7°C) o collector adds bluing agent to the toilet water o collector eliminates any source of water in CR DISCOVERER/PERSONS WHO CONTIBUTED TO THE URINE STUDY • • • • • • Richard Bright Thomas Addis Edwin Smith Hippocrates Thomas Bryant Frederick Dekkers