Background The excretory system in animals is involved in maintaining homeostasi

Question

Background
   The excretory system in animals is involved in maintaining homeostasis, meaning that the excretory system’s job is to maintain a stable internal chemical environment. There are four functions of the excretory (urinary) system: controlling water volume, regulating salt concentrations and eliminating non-metabolizable compounds absorbed from food and releasing hormones, mainly those involved in maintaining blood pressure. One of the important functions of excretion is the elimination of nitrogen waste. When animals metabolize nitrogen containing compounds like amino acids and nucleotides, the nitrogen in these compounds is converted to ammonia. Ammonia is a toxic compound which must be eliminated. We convert ammonia to urea, a less toxic compound, which is collected by the excretory system and then voided from the body.
   For humans, salt and water are in relatively short supply and must be conserved. Our kidneys function by filtering waste and then reabsorbing some molecules, salt and water from the filtrate. In the adult human 180 liters of filtrate are produced per day but daily urine volume is only 0.5 to 2.0 liters per day. Since blood volume in adult humans is only about 5-8 liters, this means the blood plasma is filtered 20 to 30 times each day, with most of the volume (and salts) being reabsorbed.
   In this lab you will analyze the data for someone with uncontrolled type one diabetes using the information below and then you will analyze your own urine (or someone else’s) using reagent strips for urinalysis in the lab kit. You will be checking for glucose, bilirubin, ketones, specific gravity, the presence of blood or hemoglobin, pH, protein, urobilinogen, nitrite and leukocytes. Because of the way the test strips are sent to you, these tests will not be perfect and should not be considered a medical evaluation of your health. If you have any concerns, please speak to your doctor about them.
Click here for a youtube video on Urinalysis using dip sticks or you can go to this link https://www.youtube.com/watch?v=s0Caq9ih9HM . The YouTube closed captioning is really bad but the author’s text on the screen gives the essence of what he is saying.
I have tried one Android App by BME Innovations that helps analyze the colors on a Multistix 10SG dip stick (the kind we are using). It doesn’t do a great job of matching colors but it does allow you to click on the closest match. I didn’t play with it enough to get the camera to take a picture that could be directly analyzed by the app but it might be possible. Feel free to give smart phone apps a try.

Supplies:

In the Lab Kit
Urine test strip
Paper cup
Test strip color chart  
You supply
Some kind of timer or clock
Napkin or paper towel

Procedure:
Part 1
The test strip in this picture is from someone with uncontrolled type 1 diabetes. Use this picture to fill in the table in this section and to explain how the data is consistent with this person having type one diabetes. Not all abnormal tests you see here indicate a diagnosis of diabetes but include them in your discussion anyway.

Part 2
Get out the urinalysis test strip and the color key sheet (found in the Urinalysis baggie in the lab kit) and a clock or watch (with a second hand is best). Be prepared to record your results as soon as you dip the test strip into the urine.
Urinate into the paper cup. When you are ready insert the test strip in the urine until the stick is just wet and pull it out and lay it on a paper towel or napkin and start a timer immediately. Don’t let the test strip stay in the urine longer than 2 or 3 seconds. Read the portion on the stick for each substance in order from glucose to leukocytes. Each measurement must be made at a certain time after dipping the test strip into the urine. The patches on the stick are in the correct reading order.
Compare the colors you see on the test strip and determine what the test result is. Enter the values and colors you see on the stick into the table on the Report Page. Read through the descriptions that follow and decide if your readings are normal or abnormal and enter your evaluation into the right hand column in the table.
Urinalysis Color Chart

Fill out the tables and answer the questions on the Report Page.
Example Data:

Test
Value/Color
Normal/Abnormal
Test
Value/Color
Normal/Abnormal
Glucose
30 seconds
Blue (0 mg/dl)
normal
pH
60 seconds
Orange (pH = 5.0)
normal
Bilirubin
30 seconds
Tan (negative to small)
Normal/near normal
Protein
60 seconds
Tan (negative)
normal
Ketone
40 seconds
Tan (0 mg/dl)
normal
Urobilinogen
60 seconds
Pink (0.2 mg/dl)
normal
Specific Gravity
45 seconds
Tan/orange (1.030)
Normal/near normal
Nitrite
60 seconds
White (negative)
normal
Blood
60 seconds
Yellow (negative)
normal
Leukocytes
2 minutes
Pale grey (negative)
normal

Results: I think this person is healthy because all tests are normal or near normal

Urinalysis Test Results
Glucose:
Normal- negative (blue color) colors ranging from blue (0 mg/dl) to brown (2000mg/dl).
In general the presence of glucose indicates that the filtered load of glucose exceeds the maximal tubular reabsorptive capacity for glucose. Diabetes mellitus is the chief cause of glucosuria (glucose in the urine). The sugar content of a diabetic urine may reach as high as 10,000 mg/dl, but 2,000-5,000 mg/dl values are more commonly found.
Bilirubin:
Normal – negative (light tan or yellow) Colors range through various shades of tan (small, medium and large).
Bilirubin may often appear in the urine before other signs of liver dysfunction are apparent. Bilirubin in the urine indicates the presence of liver disease or biliary obstruction. Very low amounts of bilirubin can be detected in the urine, even when serum levels are below the clinical detection jaundice.
Ketone:
Normal – negative (buff-pink) Colors range from buff-pink (trace, 5 mg/dl) to dark purple (large, 160 mg/dl).
Urine testing only detects acetoacetic acid, not the other ketones. In ketoacidosis (insulin deficiency [type one diabetes] or starvation or very low carbohydrate diet), it can be present in large amount in the urine before any elevation in plasma levels
Specific gravity:
Normal – 1.005 to 1.030. Colors range from deep blue-green in urine of low ionic concentration (1.000) through green and yellow-green in urines of increasing ionic concentration (to 1.030).
The specific gravity is a convenient index of urine concentration. It measures density and is only an approximate guide to true concentration. A specific gravity of less than 1.010 is consistent with a concentration defect. A specific gravity of larger than 1.025, in the absence of protein, glucose and other large molecular weight substances such as contrast media, usually indicates normal renal concentration and makes chronic renal insufficiency unlikely.
Blood:
Normal – negative. Color ranges from orange through green; very high levels of blood may cause the color development to continue to blue.
Hemoglobinuria (hemoglobin in urine) may indicate a hematologic disorder such as haemolytic anemia. It is also found in poisonings with strong acids or mushrooms, following burns, or in renal infection. A signficant amount of free hemoglobin is found in the urine whenever red blood cells are present in excessive numbers.
pH:
Normal – 5-8. Colors range from orange through yellow and green to blue.
The pH is seldom of diagnostic value. Phosphates will precipitate in an alkaline urine, and uric acid will precipitate in an acidic urine.
Protein:
Normal – negative (yellow). Colors range from yellow for negative through yellow-green and green to green-blue for positive reactions.
Marked proteinuria (protein in the urine, more than 4 grams per day, 600 mg/dl) is typical of the nephrotic syndrome but also occurs in severe cases of glomerulonephritis and several other disorders. Moderate proteinuria (0.5 to 4.0 gm per day, 100-600 mg/dl) is found in the vast majority of renal diseases as well as multiple myeloma, preeclampsia, and inflammatory, malignant, degenerative, and irritative conditions of the lower urinary tract. Minimum proteinuria (less than 0.5 gm per day, 5-30 mg/dl) is associated with chronic glomerulonephritis, polycystic disease of the kidneys. Renal tubular disorders and various disorders of the lower urinary tract. Diabetes can damage the kidneys and cause them to fail. Failing kidneys lose their ability to filter out waste products, resulting in kidney disease.
Urobilinogen:

Normal – 0.1 to 1.0 (light pink/orange). Colors range from light pink/orange to dark pink.
Urinary bilinogen is increased by any condition that causes an increase in the production of bilirubin, and by any disease that prevents the liver from normally removing the reabsorbed urobilinogen from the portal circulation. Urinary urobilinogen is increased whenever there is excessive destruction of red blood cells as in hemolytic anemia. It is increased also in infectious hepatitis and various other conditions.
Nitrite:

Normal – negative (yellowish white). Colors range from yellowish white to dark pink.
Bacteriuria (bacteria in the urine) caused by some Gram negative bacteria which produce the nitrate reductase enzyme give a positive test.
Leukocytes:

Normal – negative (Light tan). Colors range from tan to park purple.
A positive leukocyte esterase test provides indirect evidence for the presence of bacteriuria.

Details on the Chemical Reactions in the Urinalysis tests.
Glucose: This test is based on a double sequential enzyme reaction. One enzyme, glucose oxidase, catalyzes the formation of gluconic acid and hydrogen peroxide from the oxidation of glucose. A second enzyme, peroxidase, catalyzes the reaction of hydrogen peroxide with a potassium iodide chromogen to oxidize the chromogen to colors ranging from green to brown.
Bilirubin: This test is based on the coupling of bilirubin with diazotized dichloroanaline in a strongly acid medium. The color ranges through various shades of tan.
Ketone: This test is based on the development of colors ranging from buff-pink, for a negative reading. To purple when acetoacetic acid reacts with nitroprusside.
Specific gravity: This test is based on the apparent pKa change of certain pretreated polyelectrolytes, poly(methyl-vinyl-ether/maleic anhydride), in relation to ionic concentration. In the presence of bromthymol blue, colors range from deep blue-green in urine of low ionic concentration through green and yellow-green in urines of increasing ionic concentration.
Blood: This test is based on the peroxidase-like activity of henmoglobin, which catalyzes the reaction of diisopropylbenzene dihydroperoxide and 3,3’,5,5’-tetramethylbenzidine. The resulting color ranges from orange through green; very high levels of blood may cause the color development to continue to blue.
pH: This test is based on the double indicator (methyl red/bromthymol blue) principle that gives a broad range of colors covering the entire urinary pH range. Colors range from orange through yellow and green to blue.
Protein: This test is base on the protein-error-of-indicators (tetrabromphenol blue) principle. At a constant pH, the development of any green color is due to the presence of protein. Colors range from yellow for negative through yellow-green and green to green-blue for positive reactions.
Urobilinogen: This test is based on the modified Ehrlich reaction, in which para-diethylaminobenzaldehyde in conjunction with a color enhancer reacts with uruobilinogen in a strongly acid medium to produce a pink-red color.
Nitrite: This test depends upon the conversion of nitrate (derived from the diet) to nitrite by the action of Gram negative bacteria in the urine. At the acid pH of the reagent area, nitrite in the urine reacts with para-arsanilic acid to form a diazonium compound. This diazonium compound in turn couples with 1,2,3,4-tetrahydrobenzo(h)quinoline-3-ol to produce a pink color.
Leukocytes: Granulocoytic leukocytes contain esterases that catalize the hydrolysis of the derivatized pyrrole amino acid ester to liberate 3-hydroxy-5phenyl pyrrole. This pyrrole then reacts with a dazonium salt to produce a purple product
References:
   •   Biological Investigations Form, Function, Diversity, and Process, 6th edition, warren D. Dolphin, McGraw Hill p.361-362
   •   UTMB Point of Care Testing Procedures Policy, Urinalysis, ChemStrip and Multistix

Report Page:   Name  
Part 1

Fill in the table below with the value and color for each test and whether or not this is a normal reading or not. The example above is a guide to show you how to fill out the table. Below the table is an area to explain how the data is consistent with this person having type one diabetes. Not all abnormal tests you see here indicate a diagnosis of diabetes but include them in your discussion anyway.

Value/Color
Normal/Abnormal
Glucose
30 seconds

Bilirubin
30 seconds

Ketone
40 seconds

Specific Gravity
45 seconds

Blood
60 seconds

pH
60 seconds

Protein
60 seconds

Urobilinogen
60 seconds

Nitrite
60 seconds

Leukocytes
2 minutes

Results (analysis of all abnormal results):
Explain how the data is consistent with this person having type one diabetes.
Part 2
Your Data:

Do not try to analyze these results. I put this part in because I thought you would enjoy seeing how the test is actually done. The test strips have not been treated appropriately and are unlikely to be accurate. Remember that these tests will not be perfect and should not be considered a medical evaluation of your health. If you have any concerns, please speak to your doctor about them.

Value/Color
Normal/Abnormal
Glucose
30 seconds

Bilirubin
30 seconds

Ketone
40 seconds

Specific Gravity
45 seconds

Blood
60 seconds

pH
60 seconds

Protein
60 seconds

Urobilinogen
60 seconds

Nitrite
60 seconds

Leukocytes
2 minutes

Explanation / Answer

1) Type 1 diabetes occur as a result of deficiency of insulin. In urinalysis of type 1 persons, the following results are seen,

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