Week 2 AUBF Introduction- Renal Function PDF

College of Health Sciences BS Medical Technology Ketonuria Proteinuria D...

College of Health Sciences BS Medical Technology Ketonuria Proteinuria DM Type 1 Occurs in patients with DM Type 1 and in pregnant Preeclampsia women Defined as a new onset hypertension of hypertension accompanied by signs of organ injury- including the kidneys Accompanied by excess protein in the urine Organ injury typically resolves within several days or weeks after delivery Glucosuria Diabetes A chronic health condition Occurs when blood glucose becomes too high Results when the pancreas does not produce enough insulin or when the body cannot effectively use the insulin it produces College of Health Sciences BS Medical Technology  Pyuria UTI common infections that occur when bacteria infect the urinary tract Hematuria Glomerulonephritis Damage to the filtering part of the kidneys- glomerulus College of Health Sciences BS Medical Technology  Analysis of Urine and Other Body Fluids ST EP HAN Y M AE S. CH I, RMT INST RU CTO R College of Health Sciences BS Medical Technology Discussion 01 Introduction to Urinalysis Outline 02 Renal Function 03 Physical Examination of Urine College of Health Sciences BS Medical Technology Urinalysis Where it all began. Urinalysis was actually the beginning of laboratory medicine. Invention of microscope in the 17th century led to the examination of urinary sediment and to the development of quantitating the microscopic sediment. Hippocrates wrote a book on “uroscopy” in the 5th century BCE. Frederik Dekker discovered albuminuria in the year 1694 by boiling urine. Richard Bright introduced the concept of urinalysis as part of a doctor’s routine patient examination in 1827.  College of Health Sciences BS Medical Technology Despite the advances in modern medicine, why does urinalysis remain an integral part of patient examination? U R INA L YS I S –A urine specimen is readily available and easily collected. –Inexpensive Urine Composition 95% water; 5% solutes Organic solids Inorganic solids Other substances Urea Chloride Hormones Creatinine Sodium Vitamins Uric acid Potassium Medications U R IN A L YS IS Q1. What is the best way to determine whether a fluid is urine? The best way to determine whether a fluid is urine to consider the components of the specimen. CREATININE, UREA, SODIUM AND CHLORIDE are significanlty higher in urine than in other body fluids. College of Health Sciences BS Medical Technology U R IN A L YS IS  College of Health Sciences BS Medical Technology Urine Volume Normal DAILY urine output: 1200-1500 mL U R IN A L YS IS Urine volume depends on the amount of water that the kidneys excrete. Q2. What are the factors that influence urine volume? fluid intake fluid loss from nonrenal sources ADH secretion variation need to excrete increased amounts of dissolved solids  College of Health Sciences BS Medical Technology Definitions U R IN A L YS IS Oliguria Anuria Nocturia Polyuria a decrease in urine cessation of urine flow increase urine excretion increase in daily urine output at NIGHT volume (less than 1 mL/kg/hr (greater than 2.5 L/day in in infants, less than 0.5 adults and 2.5 to mL/kg/hr in children, and 3 mL/kg/day in children) less than 400 mL/day in adults)  College of Health Sciences BS Medical Technology Q3. What is the difference between Diabetes Insipidus and Diabetes Milletus? U R IN A L YS IS  College of Health Sciences BS Medical Technology Specimen Collection U R IN A L YS IS Specimens must be collected in a clean, dry, leakproof container Recommended capacity: 50 mL Labels must be attached to the CONTAINER and NOT ON THE LID Additional information on the requestion form may include method of collection or type of specimen, possible interfering medications and patient’s clinical information College of Health Sciences BS Medical Technology U R IN A L YS IS  College of Health Sciences BS Medical Technology Specimen Rejection U R IN A L YS IS 1. Specimens in containers that are unlabeled or improperly labeled 2. Labels and requisition forms that do not match 3. Specimens contaminated with feces or toilet paper 4. Containers with contaminated exteriors 5. Specimens of insufficient quantity 6. Specimens that have been transported improperly 7. Specimens that have not been preserved correctly during a time delay 8. Specimens for urine culture collected in a nonsterile container 9. Inappropriate collection for the type of testing needed (for example, midstream clean-catch specimen for bacterial culture)  College of Health Sciences BS Medical Technology Specimen Handling U R IN A L YS IS After collection, the specimen should be delivered to the laboratory PROMPTLY. It must be tested within 2 HOURS. If it cannot be tested within 2 hours, it should be REFRIGERATED or have an appropriate chemical preservative College of Health Sciences BS Medical Technology U R IN A L YS IS  College of Health Sciences BS Medical Technology Specimen Preservation U R IN A L YS IS Q4. What is the method of urine preservation that is most routinely used in the laboratory? Q5. What must be done to refrigerated urine specimens before performing urine strip testing? Q6. What is the ideal preservative for urine specimens? College of Health Sciences BS Medical Technology U R IN A L YS IS  College of Health Sciences BS Medical Technology Types of Urine Specimen U R IN A L YS IS Q7. What is the most common type of urine specimen received in the laboratory? Q8. What type of urine specimen is considered the “the ideal screening specimen”? College of Health Sciences BS Medical Technology U R IN A L YS IS  College of Health Sciences BS Medical Technology STAMEY-MEARES TEST FOR PROSTATITIS UR IN A L Y S I S Traditional four-glass urine collection technique VB1- first 10 mL of urine; represents urethral specimen VB2-10 mL of urine; represents the bladder specimen EPS- fluid collected during prostatic massage VB3- first 10 mL of urine collected after EPS.  College of Health Sciences BS Medical Technology Drug Specimen Collection U R IN A L YS IS Chain of Custody process that provides documentation of proper specimen identification from time of collection, to the receipt of lab results. it is a standardized form that must document and accompany every step of drug testing from collector to courier to laboratory to medical review officer to employer. Urine Container Capacity Urine Volume Required Urine temperature 60 mL 30-45 mL 32.5-37.7 deg C  College of Health Sciences BS Medical Technology U R IN A L YS IS Renal Function College of Health Sciences BS Medical Technology U R IN A L YS IS  College of Health Sciences BS Medical Technology Renal functions –Renal blood flow UR IN A L Y S I S –Glomerular filtration –Tubular reabsorption –Tubular secretion College of Health Sciences BS Medical Technology U R IN A L YS IS College of Health Sciences BS Medical Technology U R IN A L YS IS College of Health Sciences BS Medical Technology U R IN A L YS IS  College of Health Sciences BS Medical Technology Cellular structure of the Glomerulus – capillary wall membrane UR IN A L Y S I S fenestrated endothelium – basal lamina – visceral epithelium of the Bowman’s capsule podocytes shield of negativity Glomerular Pressure – hydrostatic pressure – oncotic pressure – pressure of fluid within the Bowman’s capsule – autoregulatory mechanism of the juxtaglomerular apparatus  College of Health Sciences BS Medical Technology Renin-Angiotensin- U R IN A L YS IS Aldosterone System College of Health Sciences BS Medical Technology U R IN A L YS IS College of Health Sciences BS Medical Technology U R IN A L YS IS  College of Health Sciences BS Medical Technology Tubular Reabsorption – Reabsorption mechanisms Active transport UR IN A L Y S I S – requires a carrier protein Passive Transport – movement of molecules across a membrane due to the existence of gradients Concepts – Maximal reabsorptive capacity – Renal threshold  College of Health Sciences BS Medical Technology Tubular Concentration – renal concentration begins in the DLoH and ALoH – countercurrent mechanism UR IN A L Y S I S serves to maintain the osmotic gradient of the medulla – final concentration of the filtrate through reabsorption of water begins in the late DCT and continues in the collecting duct  College of Health Sciences BS Medical Technology Important Hormones Aldosterone Antidiuretic Hormone (ADH) UR IN A L Y S I S – produced by the – produced by the adrenal cortex hypothalamus – regulates reabsorption – released by the of sodium in response posterior pituitary to body’s need for gland when the amount of water in the body sodium decreases – prompts reabsorption – renders the walls of the of sodium in the DCT DCT and CD permeable or impermeable to water  College of Health Sciences BS Medical Technology Tubular Secretion – involves passage of substances from the blood in the peritubular capillaries to the tubular filtrate – serves two major functions: UR IN A L Y S I S eliminating waste products not filtered by the glomerulus – major site for the removal of nonfiltered substances: PCT regulating acid-base balance in the body through secretion of hydrogen ions  College of Health Sciences BS Medical Technology Acid-Base Balance – buffering capacity of the blood depends on HCO3- UR IN A L Y S I S College of Health Sciences BS Medical Technology U R IN A L YS IS  College of Health Sciences BS Medical Technology Renal Function Tests U R IN A L YS IS Glomerular Filtration Tests standard test used to measure the filtering capacity of the glomeruli are termed “CLEARANCE TESTS” measures the rate in mL/min substance analyzed must be one that is neither reabsorbed nor secreted by the tubules; must be stable in the urine other factors to consider: consistency of the plasma level substance’s availability to the body availability of tests to analyze the substance  College of Health Sciences BS Medical Technology Urea clearance Inulin clearance New substances used in – earliest GFT – inulin- polymer of fructose testing – 40% of filtered urea is – extremely stable; not – creatinine reabsorbed reabsorbed nor secreted by waste product of muscle tubules – normal values were metabolism – not a normal body UR IN A L Y S I S adjusted to reflect constituent – B2M reabsorption – must be infused IV at a – Cystatin C – patients hydrated to constant rate throughout – radioisotopes produce a urine flow of 2 the testing period mL/min – ORIGINAL REFERENCE METHOD  College of Health Sciences BS Medical Technology Creatinine clearance (Computations) – GFR- reported in mL/min UR IN A L Y S I S  College of Health Sciences BS Medical Technology Estimated GFR (eGFR) – MDRD (Modification of Diet in Renal Disease) – MDRD-IDMS recommended by th National Kidney Disease UR IN A L Y S I S Education Program  College of Health Sciences BS Medical Technology Cystatin C Radionucleotides B2M – exogenous procedure – disssociates from HLA a – small protein produced constant rate – more labor intensive and UR IN A L Y S I S at a constant rate by all costly – may be used to nucleated cells – allows for determination of distinguish disorders of GFR and visualization the kidneys as either – immunoassays are glomerular or tubular available for measuring – may be used to measure viabilityof transplanted kidney – used to identify ESRD and cystatin C early detection of kidney – e.g. transplant – independent of muscle 125-I-iothalamate – NOT RELIABLE IN mass 51 Cr-EDTA PATIENTS WHO HAVE A 99-Tc-DTP HISTORY OF IMMUNOLOGIC DISORDERS  College of Health Sciences BS Medical Technology Tubular Reabsorption Tests – the loss of tubular reabsorption capability is often the first function affected in renal disease. – tests for tubular reabsorption are called UR IN A L Y S I S CONCENTRATION TESTS  College of Health Sciences BS Medical Technology Tubular Reabsorption U R IN A L YS IS  College of Health Sciences BS Medical Technology Currently, renal concentrating testing is performed after various periods of fluid deprivation, measuring urine and often UR IN A L Y S I S serum osmolality. Parameter measured Normal values Urine osmolality 800 mOsm or higher; range (50-1400 mOsm) Urine-to-serum osmolality ratio 3:1 Serum osmolality 275-300 mOsm Additional testing is needed when there is failure to concentrate urine. Patient may be injected with ADH to determine the cause of diabetes insipidus (neurogenic vs. nephrogenic DI) College of Health Sciences BS Medical Technology U R IN A L YS IS College of Health Sciences BS Medical Technology U R IN A L YS IS  College of Health Sciences BS Medical Technology Technical Factors to Consider Osmolality Measurements – Lipemic serum – Freezing-Point Osmometers insoluble lipids produces erronoues results with both vapor pressure and freezing-point osmometers freezing-point depression was the first principle – Lactic Acid UR IN A L Y S I S incorporated into clinical osmometers values that are falsely elevated due to lactic acid determine the freezing point of a solution by formation with both methods supercooling a measured amount of sample to – Volatile substances approximately 27 deg C. e.g. ALCOHOL Vapor pressure do not detect the presence of volatile – Vapor Pressure Osmometers substances – actual measurement measured is the “dew point” Measurements mades using freezing-point osmometers will be elevated  College of Health Sciences BS Medical Technology Free Water Clearance – determined by first calculating the osmolar clearance and the subtracting the osmolar UR IN A L Y S I S clearance value from the urine volume in mL/min. – determines the ability of the kidney to respond to the body’s state of hydration  College of Health Sciences BS Medical Technology Tubular Secretion and Renal Blood Flow PSP makes use of the dye phenolsulfonpthalein U R IN A L YS IS no longer used due to difficulty in the standardization and interpretation of PSP results PAH Test has disadvantage of being exogenous all plasma PAH is secreted by the PCT volume of plasma flowing through the kidneys determines the amount of PAH excreted in urine Titratable Acidity and Urinary Ammonia the ability of the kidney to produce an acid urine depends on the tubular secretion of hydrogen ions as well as production of ammonia by the cell of the DCT Specimen: fresh urine specimens; spc preserved with toluene and collected at 2-hour intervalsn (from Px who have been primed with an acid load consisting of oral ammonium chloride)