Introduction:
Your kidneys play a very important role in your health because their job is to remove toxins or poisons from your
blood. Obtaining information about whether a patient’s kidneys are functioning properly in an emergency situation can
literally mean “life or death.” One of the quickest ways a doctor can tell if the kidneys are functioning properly is to
examine their product – that little yellow liquid we call urine.
In this investigation you will learn to conduct a number of tests that a medical laboratory technologist, or lab tech,
might perform on a sample in a clinical hospital laboratory.
Learning objectives:
1. Test a normal urine sample and compare to a set of standards.
2. Test a urine sample from an individual with a pathological condition and determine the disorder using this data.
3. Write a letter to the attending physician that explains this condition, the current treatments for the condition,
and prognosis if left untreated. (note: these last items are normally done by the physician and not the med
tech.)
Materials:
Hydrometer
Hydrometer jar
50 mL graduated cylinder
Multi test urine strips*
2 laboratory report forms
pipettes
Microscope
flasks of urine samples
biuret reagent
test tubes and rack
slide and coverslip
* The urine test strips are extremely sensitive. The will detect trace amounts of the chemical they are designed to test
for. Hold the strips by their plastic handle ONLY, and do not set them down on the lab bench.
Your Patients:
Patient #1 – Jeff is 19 years old. He notices that he has increased urine output (polyuria), increased appetite, and a
great thirst. He has also experienced unexplained weight loss.
Patient #2 – Mr. Thompson is 60 years old and has been unusually tired for several weeks. He occasionally feels dizzy
and lately he finds it increasingly difficult to sleep at night. He has swollen ankles and feet and his face looks puffy. He
experiences burning pain in his lower back, just below the rib cage. He also notices that his urine is dark in color. He
goes to see his physician, who finds that he has elevated blood pressure, and that the kidney region is sensitive to
pressure.
Patient #3 – Mrs. Smith is 27 years old and has been experiencing painful and difficult urination (dysuria), frequency of
urination and urgency.
Methods:
1. Obtain a normal urine sample and a laboratory report. Use the following to complete the information on the
side and at the bottom:
a. The “requesting doctor” is “Dr. I.P. Freely”
b. The “nurse” attending this patient is nurse “Urethra Franklin”
c. Use today’s date and current time as the “date” and “time” collected.
d. Use the date that you finish as the “date done”.
e. Under “remarks” you usually have 3 options for the source of the urine:
1. VOID – one, complete urination from beginning to end.
2. CATH – the sample was removed from a pouch connected to a catheter (tube) inserted
into the patient’s urethra. This is often done for patients who would have problems
walking to a bathroom due to surgery or paralysis.
3. MIDSTREAM – sample collected during the middle of a urination event
Assume your sample was a “voiding” sample.
f. “Tech” = your name
g. In the big blank area, put your patient’s name. For your normal sample, put “normal”.
h. At the bottom of the form you have 5 options to indicate the status of your patient.
1. Admission: your patient has been admitted to the hospital and this is a baseline test to
determine the level of kidney function.
2. Routine: tests often done daily on patients as part of physical exams and are not being
tested for a specific problem
3. O/P (out patient): done for a patient who has not been admitted to the hospital, but
must report to the hospital lab in order to have the test done. They are then allowed to
leave and go home immediately following the test.
4. PRE-OP: done before a patient has surgery to make sure that kidneys are functioning
properly.
5. STAT: needed immediately as in an emergency case
Assume the normal sample you are running is “routine”.
i. Color: Circle the color that best describes the appearance of your sample.
1. Pale yellow – may be almost colorless to a slight yellow cast.
2. Straw – slightly darker shade of yellow
3. Amber – golden color
4. Red – may indicate presence of blood, although blood can be present w/o red color.
j. Clarity: can be an indicator of a bacterial infection.
1. Clear – translucent like water.
2. Slightly cloudy – a bit hazy
3. Cloudy – distinct haziness
4. Turbid – very foggy appearing to a point that you cannot read through it.
k. Specific gravity: Urine is a solution of water and dissolved material (solutes). Therefore, urine weighs
more and is denser than distilled water. Specific gravity is the comparison of how much heavier than
distilled water a solution is. The specific gravity of distilled water is 1.0. The specific gravity of urine
ranges from 1.001 (very dilute) to 1.035 (very concentrated).
The specific gravity of urine is measured using a urinometer and a hydrometer. The urinometer looks
like a graduated cylinder without markings on the side. The hydrometer looks like a glass “float” that
has a small lead shot in the bottom and a paper with numbers in the neck of it. Be careful with both as
they are very expensive!
1. Use a 50mL graduated cylinder to measure out EXACTLY 40mL of your sample and
transfer it to the urinometer. GENTLY place a hydrometer into the urinometer with the
urine sample. Be careful not to drop the hydrometer in the urine sample. If the
hydrometer hits the bottom of the cylinder too hard it could break. Read the specific
gravity value at the level of the surface of the urine. Record the value in the appropriate
blank on the yellow lab report from.
l. Ketones, Glucose, Protein, pH: These tests will be performed with a plastic, multi-test strip that will
allow you to perform all 4 tests at once. Timing is very critical, so tests need to be read at as close to the
60 seconds after the strip is dipped into the urine.
1. Dip the test strip into the urine sample in the urinometer and then remove it and set it
on a clean white paper towel. At the end of 60 seconds, compare the pH part of the
strip against the color scale on the side of the bottle that the strips came from. The pH
usually ranges 4.5-8, but early morning samples are typically 5-6. Uric acid is produced
as a product of nucleic acid breakdown. The pH reflects the ability of the body’s normal
acid/base buffer system to function properly. An excess of protein and whole-wheat
products can cause urine to be acidic. A vegetarian diet can cause urine to be alkaline.
Bacterial infections can also cause urine to be alkaline. Circle the pH on the appropriate
part of the yellow form.
2. Read the test for ketones. Ketones often result from the incomplete breakdown of
certain amino acids. The abundance of phenylketones, for example, may indicate PKU.
Circle the appropriate number on your yellow report form.
3. Read the test for glucose. Glucose in the urine may indicate diabetes mellitus. Circle
the appropriate number on your yellow report form.
4. Read the test for protein. Urine is usually free of protein. They are large molecules that
will not pass through the walls of the glomerular capillaries when the nephrons produce
urine filtrate. Protein in the urine may indicate conditions like hypertension or
glomerulonephritis. Circle the appropriate number on your yellow report form.
5. We will leave the urobilinogen and nitrite sections blank.
6. Leukocytes are a type of white blood cell that help fight off infections. To test for
leukocytes, you must place one drop of the sample on a microscope slide. Place a
coverslip on top. Observe under high power. Look for blue “spheres”. Circle the
appropriate value. You will use the same slide to check for blood in the sample.
7. Blood should not be present in the urine. This could indicate hypertension in which
excess pressure forces blood through the walls of the glomerular capillaries. This force
can cause permanent damage to the nephrons if allowed to persist for long periods. The
condition of blood in the urine is called hematuria and can indicate trauma to the
urinary tract, kidney stones, infection, or hypertension. Look for red “spheres” on your
slide made in part #5 above. Also look for any crystals that may be visible. The presence
or type of crystal seen can indicate disorders such as kidney stones, liver disease, or
gout.
m. Protein: An alternate test for protein involves an indicator called biuret reagent. Note: you will use a
sample known to have protein in it instead of the normal sample to observe this test.
1. Use a clean graduated pipette to add 1mL of urine to a clean glass test tube.
2. With a new pipette, add 2mL of biuret reagent to the tube. (note: biuret will be light
blue if no protein is present).
3. Gently swirl the test tube against a white background and observe the color.
4. Wash your test tube and return it upside-down in the rack provided.
What you will turn in:
1.
A yellow lab report form with the appropriate information completed for a normal urine sample and an
abnormal patient.
2. A letter to the attending physician from you (the lab tech) indicating:
a. Condition that the test results indicated.
b. An explanation of what the condition is and its symptoms.
c. The current treatment for this condition.
d. The prognosis for this individual indicating chances of recovery following treatment and complications
that could result if the condition is not treated.