Today’s lab exercise is about diagnostic Urinalysis. Urine reflects the many chemical components found in blood. This test is a good measure of health of endocrine system, kidneys, and urinary tract. Artificial urine samples are used for today’s lab thank goodness. The test that this lab is mostly focused on is called “dipstick” urinalysis test where students will analyze the chemical composition of urine by dipping the chemical indicator stick or “dispstick” into a sample of urine. The chemicals in the pad of the indicator stick will react with various biochemicals, ions and salts found in urine and indicate the presence of hemoglobin, glucose, ketones, protein and specific gravity. The change in color indicates the quantity and presence of particular urine component. High level of glucose indicates the endocrine system’s inability to regulate sugar concentration. Dilute urine indicates the adrenal gland defect that prevents kidney from regulating water and salt levels. Urine containing blood and protein indicates damage to a Kidney’s blood filtering system.
No hypothesis is necessary as this lab is an observational lab Objectives:
The objective of today’s lab is to learn and understand diagnostic urinalysis. The focus of today’s lab is geared more towards dipstick analysis. Students are to complete the chart, answer all associated questions, and include references. Students will learn the importance of urine and the various diseases/problems that can be diagnosed using it. Students will diagnose the unknown samples of “Jane and John”.
1. Acetoacetic acid
3. Urine test strips – multisticks that can measure blood, glucose, ketones, pH and protein are required and should be also able to measure specific gravity – are needed. Brand recommended is Clinistick TM .
4. Five test tubes per group
Procedure 1 (Calibration)
This is to ensure that the data collected from the patient is accurate. You will be provided with the positive and negative standard solution. The Positive Standard determines whether the indicator determines the correct response to presence of chemicals in the urine. A false positive when using water will indicate that the “stick” is detecting substances that are not there. A false negative indicates that the stick is unable to detect the presence of substances that are present in the sample. 1. Obtain the negative and positive standard bottles. Note the color on the indicator stick prior to start of experiment. 2. Collect 2 tubes and label as “neg” and “pos” for negative and positive standard solution. 3. Pour ¾ full of the tube with “neg” solutions in the tube labeled “neg.” 4. Pour ¾ full of the tube with “pos” solutions in the tube labeled “pos.” 5. Insert the indicator stick in the tube labeled “neg.” Observe the color and odor of the solution. 6. Insert the indicator stick in the tube labeled “pos.” Observe the color and odor of the solution. 7. Record your data in the table as “+” or “ –“ to indicate positive or negative result.
Procedure 2 (analysis of samples)
Obtain a set of the urine samples to analyze.
1. Collect and label three tubes as normal (N), John , and Jane.
2. Pour Normal urine sample ¾ full of the tube labeled N
3. Pour John’s urine sample ¾ full of the tube labeled John
4. Pour Jane’s urine sample ¾ full of the tube labeled Jane
5. Insert the indicator stick in the tube labeled N. Observe the color and odor of the solution.
6. Record the data
7. Perform the same test on the samples labeled John and Jane using new sticks and record your observation in the table provided above.
Please refer to the attachment for interpretation of Urinalysis results. If not provided please ask your Instructor for the same.
This lab discussed urinalysis. Urinalysis is a diagnostic test that evaluates health of endocrine system, kidneys, and urinary tract. Urine can be visually examined sample for color (clear to dark yellow or red), and clarity (clear to cloudy), and odor. A complete diagnostic urinalysis includes a dipstick evaluation and a microscopic analysis. Dipstick evaluation includes parameters such as glucose, ketones, pH, protein, blood, bilirubin, etc. The microscopic visualization allows for detection of bacteria (UTI), RBCs, crystals (metabolic derangements), renal tubular cells (toxicity or severe renal disease), or transitional cells (from bladder). Acid urine and alkaline urine have crystals that form different from that of normal urine.
Some terms that the students learned were glycosuria-excess glucose levels, hematuria-RBCs present in urine, hemaglobinuria-hemoglobin pigment is present in urine, ketonuria-high levels of ketones, myoglobinuria-high levels of myglobin (pigments that are released when muscles breakdown), and pH-measure acidity or alkalinity of urine. In order to be certain that values are correct, known negative and positive standards are used to compare with the clinical sample. This process is called calibration. Calibration should be done for all diagnostic tests and the equipment used to make these determinations. Calibration is necessary to avoid false negative and false positives. A false positive when using water will indicate that the “stick” is detecting substances that are not there. A false negative indicates that the stick is unable to detect the presence of substances that are present in the sample. Conclusion:
In conclusion, students successfully performed a urinalysis dipstick test. The lab had students test the negative and positive tests, and then the James and Jane urine samples were tested. John’s urine was clear and tested negative for protein, which indicated it was normal. The pee was slightly turbid. The urine had a strong odor and a specific gravity of 1.005, which is lower than normal urine. The pH of John’s pee is 5 and the glucose was extremely high with 1000mg, tested with small (+) amounts of ketones and also showed trace amounts of blood.
Jane’s urine was a very light yellow with a very faint odor, tested negative for ketones, tested negative for proteins, had a pH of 6, and had a specific gravity of 1.015. The glucose was extremely high with 1000mg. Jane also showed About 250 Ery/nanoliters of blood in her urine. The protein portion of the dipstick tested for 100 (++) in Jane’s urine sample. Students learned different types of disease that could be associated with the test results that were discovered with the dipstick. Lab Questions:
1. What are the possible causes of John’s test results?
John’s urine was clear and tested negative for protein, which indicated it was normal. The pee was slightly turbid which could be caused by Lipiduria, hyperoxaluria, chyluria, pyuria, excess phosphate crystals precipitating in alkaline urine, hyperuricosuria, or contamination with vaginal mucus or epithelial cells. The urine had a strong odor which could indicate alkaline fermentation, diabetic ketoacidosis, cysteine decomposition, gastrointestinal-bladder fistulae, or could be caused by medications or diet. John’s urine was observed to have a specific gravity of 1.005, which is lower than normal urine. Decreased specific gravity is seen in excessive fluid intake, renal failure, pyelonephritis, and central and nephrogenic diabetes insipidus. False low readings of specific gravity are associated with alkaline urine (a high-citrate diet).
The pH of John’s pee is 5, which is considered to be within the normal range, but it is on the lower end which could be caused by diet and uric acid calculi. The glucose was extremely high with 1000mg, which is extremely strange due to that fact that nearly all glucose filtered by the glomeruli is reabsorbed in the proximal tubules and only undetectable amounts appear in urine in healthy patients. False positive results are seen when high levels of ketones are present and also in patient taking levodopa.
Something to remember about dipstick tests is that reagent strip tests are specific for glucose. John’s sample tested with small (+) amounts of ketones. A positive test, since ketones are not normally found in urine, is associated with uncontrolled diabetes, pregnancy without diabetes, carbohydrate-free diets, and starvation. False trace results may be seen in highly pigmented urine and in patiens taking levodopa. John’s urine also showed trace amounts of blood. 2. Of the diseases mentioned, what disease might John have?
Of the diseases mentioned, it is believed that John might have either diabetes mellitus or a renal impairment.
3. How did you come to this conclusion about John’s condition? The conclusion was made that John might have diabetes mellitus, due to the high levels of glucose, slightly lower pH, and traces of ketones. The decreased level of specific gravity, and traces of blood lead to the belief that John may have a renal impairment.
4. What are the possible causes of Jane’s test results?
Jane’s urine was a very light yellow with a very faint odor, tested negative for ketones, tested negative for proteins, had a pH of 6, and had a specific gravity of 1.015. All of these characteristics do not indicate abnormalities with Jane’s pee. The glucose was extremely high with 1000mg. False positive results are seen when high levels of ketones are present and also in patient taking levodopa.
Something to remember about dipstick tests is that reagent strip tests are specific for glucose. Jane also showed About 250 Ery/nanoliters of blood in her urine. This could indicate lower urinary tract bleeding and inflammation/infection, acute glomerulonephritis, or lupus nephritis. The protein portion of the dipstick tested for 100 (++) in Jane’s urine sample. Proteinuria is indicative of renal disease, and small amounts accompany hematuria and acute urinary tract infection. 5. Of the diseases mentioned, what disease might Jane have?
Of the diseases mentioned, Jane might have an acute urinary tract infection/inflammation, or renal disease. 6. How did you come to this conclusion about Jane’s condition? The conclusion about renal disease is because proteinuria is indicative of renal disease. Jane might instead have an acute urinary tract infection/inflammation due to not only the protein in her urine but also the blood in the urine. 7. Why is Urine useful as an indicator of the endocrine and kidney disease? Urine is as an indicator of the endocrine and kidney disease because through its protein, pH, glucose, ketones, specific gravity, and blood that can possibly be found, physicians can diagnose disease. Urine indicates diseases with the kidney because the kidney is what filters out the body fluids that become the urine.
8. What is the laboratory procedure that can be used to test the presence of certain specific biochemicals in urine? The laboratory procedures that can be used to test the presence of certain specific biochemical in urine could be microscopic analysis, or even a urine electrophoresis test 9. Which blood chemical will be found in high levels in patients diagnosed with untreated diabetes mellitus? The chemical that will be found in high levels in the blood of patients diagnosed with untreated diabetes mellitus would be glucose. 10. How does odor help in diagnosis of disease?
Odor of urine helps in diagnosing disease by merely alerting the patient that something is wrong. Because urine doesn’t have a very strong smell, if a whiff of something is particularly pungent when peeing, it may indicate that the patient could have an infection or urinary stones, which can create an ammonia-like odor. Diabetics might notice that their urine smells sweet because of excess sugar. Alkaline fermentation causes an ammoniacal smell, and patients with diabetic ketoacidosis produce a urine that may have a sweet or fruity odour. Other causes of abnormal odours are cystine decomposition (a sulphuric smell), gastrointestinal-bladder fistulae (a faecal smell), medications (eg, vitamin B6), and diet (eg, asparagus).
11. Define the following terms associated with urinalysis:
Glycosuria: Glucose normally is filtered by the glomerulus, but it is almost completely reabsorbed in the proximal tubule. Glycosuria occurs when the filtered load of glucose exceeds the ability of the tubule to reabsorb it (i.e., 180 to 200 mg per dL). Etiologies include diabetes mellitus, Cushing’s syndrome, liver and pancreatic disease, and Fanconi’s syndrome. Ketonuria: Ketones, products of body fat metabolism, normally are not found in urine. Dipstick reagents detect acetic acid through a reaction with sodium nitroprusside or nitro-ferricyanide and glycine. Ketonuria most commonly is associated with uncontrolled diabetes, but it also can occur during pregnancy, carbohydrate-free diets, and starvation. Hematuria: Hematuria can be glomerular, renal, urologic, and exercise-induced. Urologic causes of hematuria include tumors, calculi, and infections. Urologic hematuria is distinguished from other etiologies by the absence of proteinuria, dysmorphic RBCs, and erythrocyte casts.
Even significant hematuria will not elevate the protein concentration to the 2+ to 3+ range on the dipstick test. (23) Up to 20 percent of patients with gross hematuria have urinary tract malignancy; a full work-up with cystoscopy and upper-tract imaging is indicated in patients with this condition. (24) In patients with asymptomatic microscopic hematuria (without proteinuria or pyuria), 5 to 22 percent have serious urologic disease, and 0.5 to 5 percent have a genitourinary malignancy. pH: Urinary pH can range from 4.5 to 8 but normally is slightly acidic (i.e., 5.5 to 6.5) because of metabolic activity. Ingestion of proteins and acidic fruits (e.g., cranberries) can cause acidic urine, and diets high in citrate can cause alkaline urine. (15-17) Urinary pH generally reflects the serum pH, except in patients with renal tubular acidosis (RTA). The inability to acidify urine to a pH of less than 5.5 despite an overnight fast and administration of an acid load is the hallmark of RTA. In type I (distal) RTA, the serum is acidic but the urine is alkaline, secondary to an inability to secrete protons into the urine.
Type II (proximal) RTA is characterized by an inability to reabsorb bicarbonate. This situation initially results in alkaline urine, but as the filtered load of bicarbonate decreases, the urine becomes more acidic. Determination of urinary pH is useful in the diagnosis and management of UTIs and calculi. Alkaline urine in a patient with a UTI suggests the presence of a urea-splitting organism, which may be associated with magnesium-ammonium phosphate crystals and can form staghorn calculi. Uric acid calculi are associated with acidic urine. Hemoglobin: The presence of free hemoglobin in the urine, an abnormal finding, that may make the urine look dark. Hemoglobin in the urine is termed hemoglobinuria. Hemoglobin is the protein in the red blood cells which carries oxygen from the lungs to the tissues of the body and returns carbon dioxide from the tissues to the lungs.
The iron contained in hemoglobin gives red blood cells their characteristic color. Red blood cells are normally taken out of circulation after approximately 4 months; they are trapped and disassembled in the spleen, bone marrow, and liver. If, however, red cells hemolyze (break down) within the vascular system, the components are set free in the blood stream. Free hemoglobin is bound by haptoglobin (another protein) and reprocessed. But if the level of hemoglobin in the blood rises above the ability of haptoglobin to reclaim it, hemoglobin begins to appear in the urine — there is hemoglobinuria. Hemoglobinuria is a sign of a number of conditions including: acute nephritis, burns, kidney cancer, malaria, sickle cell anemia, a transfusion reaction, tuberculosis of the urinary tract, and many other conditions.
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