Lab 14: Urinary System (Part II)

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Lab 14 Urinary System (Part II)

• Dr. Kim Wilson

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INTRODUCTION

• The analysis of urine has 2 purposes. One is to
  detect body disturbances, such as endocrine or
  metabolic abnormalities, in which the kidneys
  function normally but excrete abnormal amounts of
  metabolic end products specific for a particular
  disease. The second purpose is to detect disease
  conditions within the kidneys or urinary tract
  themselves that may adversely affect the urinary
  system's ability to function efficiently in the
  maintenance of fluid, electrolyte acid-base
  balance. Urine may be analyzed both physically
  chemically using relatively simple tests in order
  to check for abnormalities. In this lab, a few
  of these physical chemical tests will be
  conducted on a sample of your own urine. For
  reference, you should review information
  pertaining to urinalysis in your textbook and in
  your lab manual (Unit 21).

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PART 1 APPEARANCE AND PHYSICAL PROPERTIES OF
URINE

• INSTRUCTIONS
• Obtain a clean specimen cup and collect a sample
  of your urine. We won't be testing the specimen
  for the presence of micro-organisms, however,
  obtain a "midstream" specimen since it yields the
  best results.
• Pour part of your specimen (approx. 10 ml) into a
  test tube and cap it. This portion will be
  allowed to set for 1 hour and then centrifuged in
  order to microscopically examine its sediments.
  Use the remaining portion of your specimen to
  perform the following physical and chemical tests.

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PART 1 APPEARANCE AND PHYSICAL PROPERTIES OF
URINE

• A. COLOR
• Freshly voided urine is often described as having
  a straw or amber colored appearance. However,
  the normal color (which is due to the presence of
  a pigment known as urochrome) may range
  considerably from person to person. Concentrated
  urine, resulting from loss of water in severe
  sweating, will be dark yellow a light amber
  yellow is more characteristic of dilute urine.
  Certain deviations from the normal amber color
  may be the result of disease, whereas other color
  changes may have no pathological significance.
  For example, a brownish yellow or green color may
  be the result of bile pigments, suggestive of
  liver disease. Likewise, a smoky brown or
  reddish-brown colored urine usually indicates
  disease, but may (on occasion) be the result of
  ingestion of plant dyes found in beets or
  rhubarb.
• Record color on Results Sheet.

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PART 1 APPEARANCE AND PHYSICAL PROPERTIES OF
URINE

• B. CLARITY (CLOUDINESS)
• A freshly voided urine sample should be clear or
  transparent. If urine is cloudy when voided or
  becomes cloudy after standing, the sample should
  be checked (by microscopic examination chemical
  tests) for the presence of mucous, pus, bacteria,
  sperm, phosphate, or urate crystals.
• Record clarity on Results Sheet.
• C. ODOR
• Normal, freshly voided urine has a
  "characteristic" odor which is believed to be due
  to the presence of volatile acids. Urine that
  has been standing for a long time at room
  temperature develops an ammonia-like odor which
  is due to the decomposition of urea by bacteria
  in the specimen. The urine of patients with
  diabetes mellitus may have an acetone odor due to
  the presence of ketones. The urine of patients
  with urinary tract infections may be
  foul-smelling, especially when the infecting
  organism is a coliform bacillus. Abnormalities
  in urine odor may simply be due to the ingestion
  of certain foods for instance, garlic and
  asparagus can give urine characteristic odors.
• Record odor on Results Sheet.

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PART 1 APPEARANCE AND PHYSICAL PROPERTIES OF
URINE

• D. REACTION (pH)
• The pH of urine is a measure of its hydrogen ion
  concentration. A pH below 7 indicates acid
  urine a pH above 7 indicates alkaline urine.
  Freshly voided urine from persons not on special
  diets is usually acid and has a pH of
  approximately 6.0 however, normal kidneys are
  capable of producing urine that can vary from a
  pH of 4.5 to a pH of 8. These variations seen in
  pH may be related to diet, medication, or
  disease. For example, persons on high protein
  diets produce a more acid urine whereas persons
  on diets high in vegetables, milk or other dairy
  products produce an alkaline urine. Persons with
  diabetes mellitus (uncontrolled) excrete urine
  containing large amounts of acid whereas persons
  with urinary tract infections or persons taking
  certain antibotics will excrete an alkaline
  urine.
• INSTRUCTIONS
• 1. Place a few ml's of fresh urine into a small
  cup. Dip a strip of pH test paper into the
  sample 2 or 3 times.
• 2. Tap the pH paper on the edge of the cup to
  remove excess urine. Wait one minute
  record the pH on the Results Sheet.

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PART 2 CHEMICAL COMPOSITION OF URINE

• A. GLUCOSE
• Glucose is the sugar most commonly found in
  urine, although other sugars such as lactose,
  fructose, or galactose may also be found under
  certain conditions. The presence of detectable
  amounts of glucose in urine is known as
  glycosuria, and it may either occur in normal or
  abnormal conditions. For example, glucose may
  normally spill into the urine following
  consumption of a heavy meal, especially one that
  contains large amounts of carbohy-drates, or in
  conjunction with emotional stress. The most
  common abnormal condition resulting in glycosuria
  is diabetes mellitus. There are several
  different tests available which check for the
  presence of glucose in urine.

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INSTRUCTIONS

• Test 1 Glucose Determination Using Clinitest
  Reagent Tablets.
• 1. Place 10 drops of water 5 drops of urine in
  a test tube.
• 2. Add 1 Clinitest tablet. Note Handle
  Clinitest tablets with extreme
  caution, using gloves. These tablets contain
  caustic soda which is highly
  sensitive to moisture from air or water.
  Excessive moisture may cause chemical burns
  or bottle explosion.
• 3. Watch while a complete boiling reaction takes
  place. (Boiling occurs because the
  concentrated sodium hydroxide in the
  tablet generates heat.) Do not shake the test
  tube during the boiling or for the
  following 15 seconds after the
  boiling has stopped.
• 4. After the 15 seconds waiting period, gently
  shake the test tube to mix the
  contents. Compare the color in the tube to
  the standard color chart (for 5 drop
  method, not 2 drop method).
• 5. Record results as Negative, Trace, 1, 2,
  3, or 4 on the Results Sheet.

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Test 2 Glucose Determination Using Diastix

• 1. Pour a small amount of urine into a small
  cup.
• 2. Dip the reagent end of the strip in urine (do
  not touch the reagent end with your hands).
  Remove immediately.
• 3. While removing, draw the edge of the strip
  against the rim of the cup to remove excess
  urine.
• 4. Compare the reagent side with the
  corresponding color chart (on bottle) at
  exactly 30 seconds.
• 5. Record results on Results sheet.

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Test 3 Glucose Determination Using Benedict's
Test

• 1. Place 5 ml of Benedict's solution in a test
  tube.
• 2. Add exactly 8 drops of urine and boil the
  solution for 2 to 5 minutes.
• 3. If the solution remains blue, the test is
  negative green is recorded as , yellow as
  , orange as , and red as .
• 4. Record results on Results sheet.

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B. KETONES

• Normally the body completely metabolizes fats to
  carbon dioxide and water. Whenever there is
  inadequate carbohydrate intake or a defect in
  carbohydrate metabolism, the body metabolizes
  increased amounts of fatty acids. When this
  increase is large, fatty acid utilization is
  incomplete and intermediate products (Ketones)
  appear in the blood and are excreted in the
  urine. Diabetes mellitus is the most important
  disorder in which ketonuria (presence of ketones
  in urine) occurs. As with glucose, there are
  several different tests available which check for
  the presence of ketones.

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INSTRUCTIONS

• Test 1 Ketone Determination Using Acetest
  Reagent
• Tablets
• 1. Place an Acetest tablet on a clean dry piece
  of paper and put 1 drop of urine on the tablet.
• 2. At 30 seconds, compare the color formed with
  the color chart.
• The color will remain unchanged or
  cream-colored in a negative test, but will
  vary from pink to purple, depending on
  the amount of ketone bodies present, in a
  positive test.
• 3. Record results on Results Sheet.

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Test 2 Ketone Determination Using Ketostix
Strips

• Place a small amount of urine in a small cup.
• Dip the reagent end of the strip in urine (do not
  touch the reagent end with your hands). Remove
  immediately.
• 3. While removing, draw the edge of the strip
  against the rim of the cup to remove excess
  urine.
• 4. Exactly 15 seconds after removing the strip
  from the specimen, compare the
  reagent side with the corresponding color chart
  (on bottle). The color will remain unchanged or
  appear cream colored (from wetting) if negative
  if positive, the color will vary from pink to
  purple depending upon the amount of ketones
  present.
• 5. Record results on Results Sheet.

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C. PROTEIN

• Normally, between 40 and 80 mg of protein is
  excreted daily, but as much as 100 - 150 mg per
  day may be considered within normal limits.
  Typically however, this normal protein isn't
  detected in the urine. Proteinuria refers to an
  increased amount of protein in the urine and is
  one of the most important indicators of renal
  disease however, this condition may also
  intermittently occur in the absence of disease -
  usually as a result of strenous physical exercise
  or severe emotional stress. Several tests are
  available for measuring urinary protein.

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INSTRUCTIONS

• Test 1 Protein Determination Using Albustix
  Reagent
• Strips.
• 1. Place a small amount of urine in a small cup.
• 2. Dip the reagent end of the strip in the urine
  (do not touch the reagent end with your hands).
  Remove immediately.
• 3. While removing, draw the edge of the strip
  against the rim of the cup to remove excess
  urine.
• 4. Immediately after removing the strip from the
  urine, compare the reagent side with the
  corresponding color chart (on bottle).
• 5. Record results on Results Sheet.

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D. BILE SALTS

• Bile salts are an essential component of bile.
  Normally the majority these
• substances are recycled in the body with only
  small amounts lost in urine (the
• loss usually isn't detectable). Hay's Test for
  bile salts involves the addition of
• sulfur to urine. Since bile salts lower the
  surface tension of the water in urine, if
• bile salts are present, the sulfur will sink.
• INSTRUCTIONS
• Hay's Test for Bile Salts in Urine
• 1. Place a small amount of urine in a small cup.
• 2. Sprinkle a little finely powdered sulfur on
  the surface of the urine. If the sulfur sinks
  at once, bile salts are present in the amount
  of 0.01 or more. If the sulfur sinks
  only after gentle agitation, bile salts are
  present in the amount of 0.0025 or more.
  If the sulfur remains floating even after
  gentle shaking, bile salts are absent.
• 3. Record results on Results Sheet.

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E. COMBINATION TESTS

• INSTRUCTIONS
• Combistix Method (Determination of glucose,
  protein, pH)
• 1. Place a small amount of urine in a small cup.
• 2. Dip the reagent end of the Combistix strip in
  urine ( do not touch the reagent end with your
  hands). Remove immediately.
• 3. While removing, draw the edge of the strip
  against the rim of the cup
  to remove excess urine.
• 4. The yellow part of the strip is the indicator
  for protein. It should be read immediately and
  compared with the color chart (on bottle).
• 5. The aqua part of the strip is the test for
  glucose. This should be read after 30 seconds by
  comparing the strip to the color chart (on
  bottle).
• 6. The orange part of the strip is the pH
  indicator. It should be read immediately and
  compared with the color chart (on bottle).
• 7. Record results on Results sheet.

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PART 3 THE MICROSCOPIC EXAMINATION OF SEDIMENT
OBTAINED FROM
URINE

• INSTRUCTIONS
• 1. Obtain the urine which has set in the test
  tube for 1 hour.
• 2. Read the Discussion (below) and complete the
  Procedure (below).

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PROCEDURE

• 1. Place 10 ml of fresh urine in a centrifuge
  tube and centrifuge for 5 minutes.
  (Precaution Make certain the centrifuge is
  balanced with another tube containing 10 ml of
  urine or water.)
• 2. Pour out all the urine possible (do this
  quickly without shaking the tube or inverting it
  for more than a moment).
• 3. Add 2 drops of Sedi-Stain to the sediment in
  the tube. Thoroughly mix the contents of the tube
  with the stain by tapping briskly on the
  bottom of the tube with the index finger.
• 4. Transfer 1 drop of the stained sediment onto a
  clean glass slide.
• 5. Cover the drop of sediment with a cover glass
  and examine it under the microscope using both
  low and high power objectives.
• 6. Identify as many of the substances in the
  sediment as possible by comparing them with
  Figures 1 - 4 (see attached page - this
  handout), as well as with the urine chart (on the
  materials table in the lab). Make a drawing of
  your observations (white paper, high power). Be
  certain to properly label your drawing.
• 7. Include your drawing in your lab report.
• ANSWER THE QUESTIONS FROM THE QUESTIONS SHEET.