Presentation on theme: "An introduction to Urinalysis as performed in the Clinical Laboratory."— Presentation transcript:
1An introduction to Urinalysis as performed in the Clinical Laboratory. It’s not just water !An introduction to Urinalysisas performed in theClinical Laboratory.
2Student Objectives:Upon completion of this lecture presentation and the laboratory analysis, students will be expected to:1. Describe the major functions of the kidney.2. List the major structures of the kidney involved in urine formation.3. Describe the importance of performing Urinalysis.
3Student Objectives - continued: 4. Observe the various urine elements detected via dipstick chemical analysis.5. Observe the basic cell types found in the microscopic analysis of urine sediment.6. Name the clinical laboratory professionals who perform urinalysis testing and explain the education each requires.
4Topics This presentation covers the following topics: What is Urinalysis?Review of kidney functionMacroscopic examination of urineChemical examination of urineMicroscopic examination of urineWho performs urinalysis testing?Summary and References
5Courtesy of the National Library of Medicine What is Urinalysis?Urinalysis – or the analysis of urine – is one of the oldest laboratory procedures in the practice of medicine.It is a good test for assessing the overall health of a patient.Courtesy of the National Library of Medicine
6What is Urinalysis? It provides information about: The state of the kidney and urinary tract.Metabolic or systemic (non-kidney) disorders.Urinalysis can reveal diseases that have gone unnoticed because they do not produce striking signs or symptoms.Examples include diabetes mellitus, various forms of kidney failure, and chronic urinary tract infections.
7Review of Kidney Function Urine is composed of approximately 96% water and 4% dissolved substances derived from food or waste products of metabolism.The actual composition of urine varies, depending on diet, metabolism, general health of the body, and health of the kidney.Urinalysis is performed to assess the urine’s composition as well as kidney function.
8Review of Kidney Function Recall the urinary system consists of two kidneys, two ureters and the bladder.
9Review of Kidney Function Also recall the role of blood - to bring nutrients and oxygen to cells of the body and to carry waste materials away from those cells.The kidney has the largest role in controlling the chemical composition of the blood in order to maintain proper cell function in the body.
10Review of Kidney Function In the kidney, blood undergoes filtration and dialysis to separate waste compounds that will be removed from the body from those that will be returned to the circulating blood.Figure 1
11Review of Kidney Function More specifically, the kidney has the functions of:removal of waste products from the bloodretention of nutrients such as proteins and glucosemaintenance of acid-base balanceregulation of water and electrolyte (salt) content of the bodyhormone synthesis
12Review of Kidney Function Urine is formed in the kidney structure called the nephron.Each kidney contains about one million nephrons.The nephron is made up of a glomerulus and a set of tubules.Cross section of a nephron
13Review of Kidney Function The tubular portion of the nephron consists of several structures:Proximal convoluted tubuleLoop of HenleDistal convoluted tubuleCollecting duct
14Review of Kidney Function Urine is formed through a three phase process of:FiltrationReabsorptionSecretion
15Review of Kidney Function Filtration of the blood occurs within the specialized collection of capillaries in the glomerulus.The glomerulus permits water and small molecules and ions from the blood to enter a surrounding tubule called the Bowman’s capsule. This is called the filtrate.Blood cells and large protein molecules remain in the blood and return to the venous circulation.
16Review of Kidney Function Reabsorption of essential chemicals the body needs (glucose, amino acids, NaCl and other salts, water and vitamins) occurs within the nephron’s proximal tubule, Loop of Henle, and distal tubule.Reabsorption prevents the loss of necessary body compounds but also adjusts the concentration of urine so it is more dilute when the body has more water (i.e., hydrated) and more concentrated when the body is short of water (i.e., dehydrated).
17Review of Kidney Function Secretion of foreign chemicals the body does not need (ammonia, drugs, hormones, toxins) begins in the proximal tubules and continues in the distal tubule and the collecting duct.Secretion of excess ions such as H+ and K+ help establish electrolyte and acid-base balance.
18Review of Kidney Function All three processes of filtration, reabsorption and secretion occur simultaneously as a result of complex cellular transport mechanisms and buffering mechanisms within the nephron tubules.The glomerular filtrate becomes more concentrated and acidic after it leaves the distal tubule and enters the collecting duct.The fluid that leaves the collecting duct is now urine.
19Review of Kidney Function The processes of glomerular filtration and renal tubular reabsorption and secretion are can become affected when the kidney is compromised by disease.Loss of renal function can be caused by variety of conditions such as:congestive heart failureinjury to the glomerulus or tubules caused by drugs, heavy metals and viral infectionsdiabetes, hypertension and kidney stones.
20UrinalysisRenal function tests, such as the urinalysis, are used to screen for the cause and the extent of renal dysfunction.Urinalysis consists of the following measurements:Macroscopic examChemical examMicroscopic exam of the sediment
21Macroscopic Exam Examination of the physical properties including…. ColorClarity (or transparency)
22Macroscopic Exam Color - normal yellow (straw to amber)Color - abnormal (due to disease, drugs or diet)pale to colorlessamber (dark yellow)orangepink or redgreenbrown or black
23Macroscopic Exam Clarity (or transparency) - normal clearClarity - abnormal (due to insoluble elements such as cells, crystals, etc.)hazycloudyturbid
25Chemical ExamThe presence of normal and abnormal chemical elements in the urine are detected using dry reagent strips.These plastic strips contain absorbent pads with various chemical reagents for determining a specific substance.
26Chemical ExamWhen the test strip is dipped in urine the reagents are activated and a chemical reaction occurs.The chemical reaction results in a specific color change.
27Chemical ExamAfter a specific amount of time has elapse, this color change is compared against a reference color chart provided by the manufacturer of the strips.
29Chemical ExamThe intensity of the color formed is generally proportional to the amount of substance present.
30Typical Substances Tested & Significance pH - partial assessment of acid base status; alkaline pH indicates old sample or urinary tract infectionSpecific Gravity - state of kidney and hydration status of patientProtein - primarily detects protein called albumin; important indicator in the detection of renal diseaseGlucose - primarily detects glucose (sugar); important indicator of diabetes mellitus
31Typical Substances Tested & Significance Blood - red blood cells, hemoglobin, or myoglobin (muscle hemoglobin); sensitive early indicator of renal diseaseKetone - normal product of fat metabolism; increased amounts seen in diabetes or starvation (extreme dieting)Bilirubin - detects bilirubin (a product of red cell breakdown); indicator of liver functionUrobilinogen - another by-product of red cell breakdown; increased amounts seen in fever, dehydration, hemolytic anemia and liver disease
32Typical Substances Tested & Significance Nitrite - certain bacteria convert normal urine nitrate to nitrite; indicator of urinary tract infectionLeukocyte Esterase - detects esterase enzyme present in certain white blood cells (e.g, neutrophils, monocytes); indicator of urinary tract infection
35(Normal for comparison) Positive Glucose(Normal for comparison)
36Positive Blood & Ketones (Normal for comparison)
37Positive Blood and Leukocyte Esterase (Normal for comparison)
38Microscopic ExamMost commonly used procedure for the detection of renal and/or urinary tract disease.This exam consists of reviewing the solid material suspended in the urine - both chemical and cellular.
39Microscopic ExamRequires a well-trained laboratory professional who is:skilled in the use of various microscopic techniques such as bright field and phase microscopyable to distinguish normal or contaminating items from abnormal, pathologic elementsknowledgeable of the clinical significance of each finding and its relationship to the chemical and physical analysis
40Microscopic ExamThe urine specimen is centrifuged and the liquid portion is poured off.The concentrated cellular sediment ….
41Microscopic Exam…. is then placed on a microscope slide, covered with a coverslip and ….
43Microscopic ExamA variety of normal and abnormal cellular elements may be seen in urine sediment such as:Red blood cellsWhite blood cellsMucusVarious epithelial cellsVarious crystalsBacteria
44Microscopic Exam Red blood cells presence of a few is normal higher numbers are indicator of renal diseaseresult of bleeding at any point in urinary system40x objective
45Microscopic Exam White blood cells a few are normal high numbers indicate inflammation or infection somewhere along the urinary or genital tract40x objective
46Microscopic Exam Mucus look like long, ribbon-like threads common finding in urine sedimentsecreted by glands in the lower urinary tract40x objective
47Microscopic Exam Epithelial cells cells are large and flat normal cells that line the urinary and genital tract or renal tubules40x objective
48Microscopic ExamA variety of normal and abnormal crystals may be present in the urine sediment.
49Microscopic Exam Crystals of calcium oxalate colorless octahedron found in acid urineCrystals of triple phosphatecolorless, “coffin-lid” prismcommon finding; not clinically significant
50Hyaline cast & epithelial cell, 40x objective Microscopic ExamHyaline Castscolorless and fatter than mucusa few are normalmay be increased after strenuous exerciseform when protein solidifies in the nephronHyaline cast & epithelial cell, 40x objective
51An additional note ...The chemical and microscopic analysis of urine can be performed manually or with automated analyzers.In many laboratories, abnormal automated findings are confirmed by manual techniques.
52Who performs urinalysis testing? In most clinical laboratories, urinalysis is performed by medical laboratory professionals called:Medical Laboratory Technicians or Clinical Laboratory Technicians (MLT/CLT)Medical Technologists or Clinical Laboratory Scientists (MT/CLS)
53What education is required to be a laboratory professional? Associate’s degreeMedical Laboratory Technician (MLT)Clinical Laboratory Technician (CLT)Bachelor’s degreeMedical Technologist (MT)Clinical Laboratory Scientist (CLS)For more info, visit our web site at
54Laboratory science careers are rated among the best! Parole officerMeteorologistTechnical writerMedical secretaryMedical technologistFinancial plannerMedical laboratory technicianAstronomerHistorianWebsite managerActuaryComputer systems analystSoftware engineerMathematicianComputer programmerAccountantIndustrial designerHospital administratorWeb developerParalegal assistantJobs Rated Almanac, L. Krantz, 1999
55Summary Urinalysis in an important clinical diagnostic test. Urinalysis can reveal diseases that have gone unnoticed because they do not produce striking signs or symptoms.Urinalysis provides information about the kidney, urinary tract, and systemic (non-kidney) disorders.The results of the macroscopic, chemical and microscopic analysis must be interpreted together to arrive at a proper diagnosis.
56SummaryAlthough urinalysis is easily performed with reagent test strips, the results are dependent on:correct techniquean understanding of the limitations and interference'sThus, technologists and technicians performing these tests must be properly trained, especially in correctly recognizing microscopic elements.
57ReferencesUrinalysis and body fluids - a colortext and atlas, Ringsrud, K & Linne, J, Mosby - Year Book, Inc., 1995.MTS Lab Training Library™, University of Washington, Department of Laboratory Medicine, 2003.Modern chemistry, Bayer Corporation, Diagnostics Division, Tarrytown, NY, 1996.Multistix 10SG Urinalysis Reagent Strips product insert AN30516C, Bayer Corporation, April, 1999.
58ReferencesFigure 1: Your Kidneys and How They Work, National Kidney and Urologic Diseases Information Clearinghouse,Figure 2: Update in Anaesthesia - Physiology of the Kidney, Issue 9 (1998) Article 6, World Anaesthesia (WA) and World Federation of Societies of Anaesthesiologists (WFSA),
59The End Students: Teachers: Perform a “Chemical Analysis” on the urine “specimens” provided by your teacher.Teachers:After students complete chemical analysis, show students the following Microscopic Images for the “Microscopic Analysis” portion of the lesson.
60Microscopic Images for Urinalysis Laboratory Lesson It’s not just water !Microscopic ImagesforUrinalysis Laboratory Lesson