General Laboratory: Urinalysis: Introduction Online Training
The urinary system excretes waste to help keep the chemicals and water in our body balanced.
Describe basic kidney structure, the function of key components, and how the kidney forms urine Describe common types of specimens collected for urinalysis testing, proper specimen containers, and how to preserve urine specimens prior to examination Describe the importance of performing routine urinalysis Welcome to the Clinical Urinalysis Introduction course. After completing this course, you’ll be able to: Select Next to continue. Welcome to the Sysmex® CS-2000i System Sample Processing Online Training course. Processing samples on the Sysmex® CS-2000i System is accomplished in a few easy steps. You begin by loading samples in a rack. Order the tests either manually or by host interface, and press start. To begin learning about Sample processing, select next to continue. Why is performing a routine urinalysis important? Urine testing provides clinicians with valuable information to confirm normal urinalysis as well as to detect metabolic and kidney disorders. Metabolic disorders include body disturbances such as endocrine or metabolic abnormalities in which the kidneys function normally but excrete abnormal amounts of metabolic end products that are specific to a particular disease. Kidney disorders include conditions that may adversely affect kidneys or urinary tract. Diseased kidneys cannot adequately regulate the volume and composition of body fluids, which makes the body unable to maintain homeostasis, the stabilization of bodily functions. Consequently, substances normally retained by a kidney, or excreted in small amounts, may appear in the urine in large quantities; or substances normally excreted may be retained. Select Next to continue. Sample Processing on the Sysmex® CS-2000i System is quick and easy. In this section we will cover how to check reagents before a run, how to process samples with a bi-directional interface, how to manually process barcoded samples, how to manually process non barcoded samples, and how to order samples in micro mode. Select Next to continue. The primary functions of the kidneys are as follows: Removal of waste products—primarily nitrogenous wastes from protein metabolism, such as urea and acids Acid-base balance Water and electrolyte balance Retention of essential nutrients, such as water, glucose, protein and electrolytes Hormone production, such as erythropoietin and renin Activation of Vitamin D Select Next to continue. Key: 1 - Kidney How can you handle running tests on a precious or small sample? The Sysmex® CS-2000i system can run samples in Micro mode where only what is needed for the ordered test is aspirated from the primary sample. Micro mode samples will not be automatically re-analyzed, reflexed or have a HIL check performed. Select the link below to learn about processing samples in Micro mode. The kidney is a highly discriminating organ that selectively excretes or retains various substances according to specific body needs. Some additional facts about the kidney include the following: Approximately 1,200 mL of blood flows through the kidneys each minute. This represents about one-fourth of the body's total blood volume. The functional unit of the kidney is the nephron. Nephrons are microscopic tube-like structures in the kidneys that filter the blood and remove waste. There are approximately one million nephrons in each kidney. Urine essentially consists of urea and other organic and inorganic chemicals dissolved in water. Let us take a look inside a kidney nephron. Key: 1 - Kidney 2 - Nephron Kidney Anatomy Did you know? Only about 500,000 nephrons are required to maintain normal kidney function. It is this excess capacity that permits someone to donate a kidney, without risking the loss of kidney function themselves. It is also the reason that a person has to lose 50 - 75% of their kidney capacity, before the usual kidney function tests start to show diminished capacity. When complete, select the X in the upper-right corner to close the window and continue. Each nephron consists of a glomerulus and a renal tubule. The glomerulus acts as an ultrafilter to keep larger molecular weight substances from entering the urine, while permitting dissolved substances to be filtered through. The system of renal tubules represents the real working area of the nephron. The filtrate that comes through the glomerulus is concentrated and refined by the special cells that line the tubules. In different parts of the tubules, specific substances are either excreted or reabsorbed to maintain electrolyte and fluid balance, as well as to eliminate toxic waste while conserving important substances. Kidney disease may be limited to the glomeruli or the tubules or it may involve the entire system. Select Next to continue. Key: 1 - Kidney 2 - Nephron 3 - Glomerulus Looking inside a kidney nephron, we can see that the glomerulus is essentially a small tuft of blood capillaries. Blood from the renal artery enters the glomerulus through the afferent arteriole. Glomerular filtration occurs as blood plasma, dissolved waste substances, and small proteins are filtered through the capillary walls of the glomerulus into an area called Bowman's capsule. The inner wall of Bowman's capsule is permeable to allow the glomerular filtrate to easily pass through it into the renal tubule. Blood that is not filtered leaves the glomerulus by the efferent arteriole and forms a capillary network around the renal tubule. 1 - Kidney 2 - Nephron 3 - Glomerulus 4 - Renal artery 5 - Afferent arteriole 6 - Bowman's capsule 7 - Renal tubule 8 - Efferent arteriole 9 - Capillary network Glomerulus Structure Did you Know? The kidneys produce approximately 180 liters of glomerular filtrate per day but only about 1.5 liters of this amount is excreted as urine—the remainder is reabsorbed back into the blood. When complete, select the X in the upper-right corner to close the window and continue. Cells that line the renal tubules reabsorb almost all glomerular filtrate back into the blood. Any remaining glomerular filtrate is excreted as urine. Renal tubule cells also secrete materials from the interstitial fluid into the glomerular filtrate to get rid of substances in the blood, such as ammonia, creatinine, and the end products of medications, for example. These materials are added to the glomerular filtrate and also excreted as urine. Let us learn more about how urine is formed: The uppermost portion of the renal tubule is the proximal convoluted tubule. About 80% of the fluid and electrolytes are reabsorbed back into the blood in the proximal convoluted tubules. The descending limb of the proximal tubule and the distal tubule form a loop known as the loop of Henle. The loop of Henle is the principle site where urine is concentrated. The distal convoluted tubule reabsorbs sodium back into the blood to maintain water and electrolyte balance, and removes excess acid to maintain the body's acid-base balance. The distal convoluted tubules from several nephrons drain remaining filtrate into a collecting tubule. The collecting ducts, under the influence of antidiuretic hormone (ADH), control the final concentration of urine. From the kidneys, urine travels down two thin tubes called ureters to the bladder for storage, where it remains until voided. 1 - Kidney 2 - Nephron 3 - Glomerulus 4 - Proximal convoluted tubule 5 - Henle’s Loop 6 - Distal convoluted tubule 7 - Collecting tubule 8 - Ureter 9 - Bladder What is Tamm-Horsfall protein? Learn more about why it is important for the renal tubules to produce the Tamm-Horsfall protein. As the urine is being formed, a mucoprotein called Tamm-Horsfall protein is produced by the distal convoluted tubules and upper collecting ducts. This protein acts as a coating and lubricant in the tubules, as the urine is formed and concentrated. Without this protection, the tubular epithelial cells would have great difficulty functioning, due to the harsh environment. If there is a reduction in the urine flow, this mucoprotein may fill the tubule and "gel," forming a cast. A classic cause of this is exercise. If a person exercises strenuously, the blood flow to the kidneys is reduced as it is re-directed to the muscles. During this period, hyaline casts may be formed in the distal convoluted tubule of the nephron. When the exercise is over, and the blood flow returns to normal, there is a "flushing out" of these casts into the urine. This "shower of casts" is usually non-pathological. When complete, select the X in the upper-right corner to close the window and continue. In order for urinalysis to be meaningful, urine must be properly collected. Improper collection may invalidate the results of the laboratory procedures, regardless of how carefully and skillfully the tests are performed. Accurate urinalysis results require: Patient preparation prior to specimen collection Appropriate specimen collection Specific containers for the specimen Preservation and transportation of the specimen Proper labeling with all appropriate information Examination and testing of the specimen as soon as possible following accepted protocols Select Next to continue. Common types of specimens collected for urinalysis testing include: Random First Morning Second Morning Timed Collection Urine Concentration Over a 24 Hour Period Learn more about how the concentration of urine varies throughout a 24-hour period. The concentration of urine varies throughout a 24-hour period, depending partly on the patient's water intake and activities. For example, various solutes may appear in greater or lesser amounts at various times of the day: Glycosuria appears more often after meals Proteinuria may occur following activity or assumption of the orthostatic (upright) position Hemoglobinuria may follow severe exertion In addition, the number of bacteria in the urine of a person with a urinary tract infection also varies greatly throughout the day When complete, select the X in the upper-right corner to close the window and continue. Types of UA Specimens Learn about types of specimens collected for urinalysis testing. Tab TitleTextRandomA portion of a single voided urine without defining the volume, time-of-day, or detail of patient preparation. While the most convenient and common type of specimen, it is also associated with many false negative and some false positive results. The specimen is good for chemical screens and microscopic examinations. Note: Because concentration may affect results, the urine's specific gravity (amount of dissolved substances present) should be considered during result interpretation. Routine tests and any other tests performed on a random specimen of urine are generally qualitative or semi-quantitative. At best, only the concentration of a substance in the specimen tested can be measured, but never the total amount being excreted unless the urine is collected over a precisely measured period of time and the volume is measured.First MorningThe specimen voided immediately after an overnight bed rest before breakfast and other activities. This has been traditionally recommended as the standard specimen for urinalysis, because it is more concentrated than the day urine and allows time for possible bacterial growth in the urinary bladder. This specimen is best for nitrite, protein, and microscopic examinations.Second MorningA single specimen voided 2-4 hours after the first morning urine. In contrast to the first morning urine, its composition may be affected by prior ingestion of food and fluids and by movement. This specimen may reflect blood glucose and typically contains intact formed elements. When complete, select the X in the upper-right corner to close the window and continue. Correcting for Varying Urine Concentrations Learn how laboratories can avoid specific errors using ratio testing. Today, there are several dipsticks on the market that offer a protein-to-creatinine ratio (P:C ratio) and albumin-to-creatinine ratio (A:C ratio), both of which correct for varying urine concentrations. The ratio results are more reliable than albumin or protein measurements alone, and reduce both false positive and false negative results compared with reference assays. These new tests enable physicians to quickly assess protein excretion using a single random urine specimen. Both the American Diabetes Association (ADA) and the National Kidney Foundation (NKF) recognize the convenience of ratio testing as compared to timed urine collection. "The analysis of a spot sample for the A:C ratio is strongly recommended. The other two alternatives (24h collection and a timed specimen) are rarely necessary. At least two of three tests measured within a 6-month period should show elevated levels before a patient is designated as having microalbuminuria." Copyright © 2004 American Diabetes Association from Diabetes Care, Vol. 27, Suppl. 1, 2004:S15-S35. Reprinted with permission from The American Diabetes Association. "The ratio of protein-to-creatinine or albumin-to-creatinine in an untimed, "spot" urine specimen corrects for variations in urinary concentration due to hydration and provides a more convenient method of assessing protein and albumin excretion than is involved with timed urine collection." National Kidney Foundation K/DOQI Clinical Practice Guidelines for Chronic Kidney Disease: Evaluation, Classification and Stratification; Am J Kid Dis 39, 2002 (Supp 1). When complete, select the X in the upper-right corner to close the window and continue. For urine collection, disposable containers of plastic or coated paper are available in many sizes; they are provided with lids to reduce bacterial and other types of contamination. Special pliable polyethylene bags are also available for collection of urine from infants and children who are not toilet-trained. For some chemical constituents, quantitative excretion measurements are important. For this purpose, large, wide-mouthed plastic or glass containers with screw caps are used for cumulative collection of urine over a long period of time. Containers designed for a 24-hour or overnight urine collection typically hold 2-3 liters and are manufactured with materials that prevent: Adherence of urine constituents Exposure of urine to direct light, which might alter clinically significant metabolites Contamination from the exterior when closed When urine is to be cultured for bacterial content, the specimen must be obtained under aseptic conditions and collected in a sterile container equipped with a tight-fitting, sterile cap. This cap is left in position until the actual time of urine collection and replaced immediately afterward. Select Next to continue. Welcome to the SYVA Go to Market Messaging Exam. This assessment is intended to test your knowledge and recall of the core messaging and benefits for Siemens Healthcare Diagnostics SYVA Drug testing markets and portfolios. Preservatives and/or refrigeration are often used to prevent metabolic and other changes of urine constituents because the time elapsing between voiding and examination of urine is a major obstacle to diagnostic accuracy in most laboratories. For many chemical constituents examined with urinalysis test strips, no preservatives are needed provided the analysis is performed within 24 hours and the specimen has been refrigerated. When rapid or refrigerated transportation is not possible, strip examination should be performed on-site. If the specimen has become contaminated with external bacteria and has not been refrigerated, compromised nitrite or protein results may be obtained with urinalysis test strips. In addition, the bacteria may possibly cause false negative glucose results. This may cause erroneous results, as casts decompose in alkaline and/or hypotonic urine and red blood cells may lyse. Marked changes in pH may also affect other cellular components. Urine Specimen Preservation Options Learn how urine specimens should be preserved. Tab TitleTextMacroscopic ExamThere is no substitute for the use of fresh urine in routine urinalysis. Whenever possible, urine should be macroscopically examined and the urinalysis test strip analyzed within two hours after voiding. If this cannot be done, then refrigeration at 5°C is the preferred storage condition. The urine specimen should be brought to room temperature before testing. Preservatives should be used cautiously, as preservatives suitable for some test procedures may interfere with others, and preservatives added to small amounts of urine will increase specific gravity, may have minor effects on pH, and may also slightly inhibit the leukocyte esterase reaction.Microscopic ExamFor particle examination, the specimen should be refrigerated if not examined within 1 hour, although urate and phosphate precipitation will occur in some specimens. If precipitation disturbs interpretation, a new specimen should be examined at +20°C. The longer the testing delay, the more likely it is for elements to lyse, especially when the urinary pH is alkaline and the relative density is low. The WBC count may be questionable after 2-4 hours, even with refrigeration. Traditionally, ethanol (50% volume fraction) is used to preserve the cells but this only partially prevents lysis of red and white blood cells. Commercial preservatives, such as formaldehyde-based solutions, buffered boric acid and formate-based solutions, and mercuric chloride-based tablets, have gained renewed interest following the development of automated systems.Microbiological ExamSpecimens requiring microbiological investigation must be collected in a clean, sterile container and examined in the laboratory within 2 hours. They should be refrigerated at 4°C without preservative if a delay >2 hours is expected. Then, they should be examined within 24 hours. If delay is unavoidable and refrigeration not possible, containers prefilled with boric acid preservative, alone or in combination with formate or other stabilizing media, ideally in a lyophilized form, may be used. Boric acid will stabilize white blood cell numbers and bacterial concentration in urine held at +20°C for 24 hours. Boric acid concentration may be critical for successful preservation without bacterial inhibition. It is suggested that containers containing boric acid should be filled to the indicated line to achieve a correct borate concentration. The specimen should be examined within 24-48 hours of production. It should be noted that borate may inhibit growth of Pseudomonas sp. When complete, select the X in the upper-right corner to close the window and continue.