10.2 Lab Protocol
Approximate Time: 3 hours
Learning Objectives
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- Normal Characteristics of Urine: Identify the normal or average characteristics of human urine.
- Abnormal Characteristics of Urine: Understand the various abnormal characteristics of human urine.
- Urinalysis Test: Understand urinalysis as a diagnostic tool.
- Urine Output Under Test Conditions: Measure urine output and parameters under various test conditions.
Obtain the following items from your lab instructor:
- Red cup (to collect urine)
- Plastic conical tube (to bring urine sample to class)
- Graduated cylinder (to measure the volume of voided urine)
Activity 1: Urinalysis
Step 1: Prepare Your Collection Cup
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- Obtain a red urine collection cup and label it with your name using a Sharpie.
- When you go to the restroom, bring all three items (red cup, graduated cylinder, and conical test tube):
- Use the red cup to collect your urine.
- Use the graduated cylinder to measure the total volume of urine (hold it over the toilet to avoid spills).
- Transfer 13 ml of urine into the conical tube, cap it securely, and to return it to the lab for chemical testing. Discard any remaining urine from the graduated cylinder into the toilet.
- Wash your hands thoroughly before coming to lab.
- After use, return the graduated cylinder, conical tube, and red collection cup to the lab. Place your red collection cup on a folded paper towel and store the graduated cylinder at the edge of the lab, not on the lab tables.
Step 2: Baseline Urine Collection (Time Zero)
- Collect a baseline urine sample.
- Record the following parameters listed in table 1
Table 1
| Characteristic | Notes |
| Time (Record the exact time of collection) | |
| Volume (Use a graduated cylinder) | |
| Color (e.g., very pale yellow, pale yellow, golden, etc.) | |
| Odor (e.g., very slight, slight, odorous, very odorous) | |
| Clarity (Clear or cloudy – note “floaties” if present) | |
| Specific Gravity (Measured by designated group member using refractometer) |
Step 3: Urinalysis Test Strip
- Remove the cap from the conical tube, then take one urinalysis strip and a reference color chart.
- Dip the test strip into the urine sample.
- Read the results from bottom to top, following the timing guidelines on the reference chart.
- Record your test results in Table 2.
- When finished, dispose the urinalysis strip in the biohazard bag and the urine sample in the toilet and clean up any spills.
Interpretation of Results
Leukocytes: Also known as white blood cells, are an essential component of the immune system that helps protect the body against infections and foreign invaders. Normally, a small number of white blood cells are present in urine, yielding negative results. However, this screening test will become positive when the number of white blood cells in urine increases significantly, Leukocytes greater than 10 leu/uL in urine may indicate infections in the urinary tract or kidneys.
Nitrites: These are chemicals that are normally present in urine. If bacteria enter the urinary tract, nitrates can be converted into nitrites, similar chemicals with a slightly different structure. Nitrites in urine may indicate a urinary tract infection (UTI). However, it is important to note that a negative nitrate test does not necessarily rule out the presence of UTI.
Urobilinogen: Urobilinogen is a byproduct resulting from the breakdown of bilirubin, a yellowish compound produced in the liver to help in breaking down red blood cells. It’s normal for a small amount of urobilinogen (up to 1.0 mg/dL) to be present in urine. However, if the urine contains little to no urobilinogen, it could suggest that the liver isn’t functioning properly. On the other hand, an excess of urobilinogen (greater than 2 mg/dL) in urine could indicate liver diseases such as hepatitis or cirrhosis.
Protein: Protein in urine test measures the amount of protein present in urine. Proteins are essential substances that help the body function properly and are normally found in the blood. If there is a problem with your kidneys, protein can leak into your urine. While small amount of protein in urine is normal, a large amount may indicate kidney disease. When urine protein is elevated, a person has a condition called proteinuria. Persistently elevated protein levels in urine can result from urological and nephrological disorders and require medical attention.
pH: A urine pH test is used to gauge the acidity level in urine. Normal urine tends to be slightly acidic, with a pH value between 5 and 8. Urine with a pH below 5.0 is considered acidic, while urine a pH above 8 is deemed alkaline. High urine pH levels (greater than 8) could indicate conditions such as urinary tract infections, kidney stones or failure, stomach pumping, or vomiting. Conversely, low urine pH levels could suggest conditions like diabetic keto acidosis, diarrhea, excessive body fluid acidity (metabolic acidosis), or starvation. Diet plays a significant role in affecting urine pH. Consuming a diet rich in fruits and vegetables can increase your urine pH, while a diet high in meat products or cheese can decrease your urine pH. Certain medications can also alter the normal pH of urine.
Uric Acid: The uric acid test measures the concentration of uric acid in the urine. Uric acid is a byproduct of the breakdown of purines, substances that are found in certain foods (like red meat, seafood, and alcohol) as well as naturally occurring in the body. Under normal circumstances, uric acid is filtered by the kidneys and exits the body through urine. Abnormally high levels of uric acid in urine, known as hyperuricosuria, can suggest health conditions such as kidney stones, where uric acid crystallizes in the kidneys, or lead to the development of gout if there is concurrent elevation in the blood. On the other hand, low levels of uric acid in urine may indicate kidney disease or other metabolic conditions that affect how they body processes purines. Factors such as diet and certain medications can influence uric acid levels, with foods rich in purines (such as meat and alcohol) tending to increase uric acid, while some treatment may help lower these levels.
Specific Gravity: Urine-specific gravity measures the concentration of all chemical particles in the urine. In healthy adults, urine specific gravity ranges from 1.003 to 1.030. A reduced specific gravity may indicate diabetes and other renal disorders, while elevated levels may indicate liver disease, excessive loss of free water, or congestive heart failure. A higher than average concentration often results from not drinking enough fluids.
Ketone: Ketones are substances the body generates when it uses fat instead of sugar as energy. This can occur when the body doesn’t have enough insulin to process sugar or when there aren’t enough carbohydrates, such as during fasting, starvation, or high-protein diets. Normally, ketones aren’t found in urine. However, they can appear when the body can’t properly utilize carbohydrates. Without carbohydrates, they body turns to fat for energy to keep functioning. An increase in ketone levels can indicate a lack of insulin and can be seen in conditions like diabetes, starvation, vomiting, digestive disorders, pregnancy, and feverish conditions. For those on a ketogenic diet, ketones in urine signify a metabolic state known as ketosis. This state leads to weight loss and fat burning.
Bilirubin: A yellowish pigment, is found in bile, a fluid that the liver generates. In healthy individuals, bilirubin typically doesn’t appear in urine. However, elevated bilirubin levels can signal liver conditions such as cirrhosis, hepatitis, gallstones, or biliary tract disease and serve as an early sign of jaundice. Even small amounts of bilirubin are unusual enough to necessitate further examination.
Calcium: Calcium in urine test measures the amount of calcium in your urine. If your urine calcium levels are too high or too low, it may be a sing of kidney disease, kidney stones, bone disease, a parathyroid gland disorder, or other condition. Normally, your kidneys filter out a small amount of calcium from your blood, which leaves your body in urine. Checking the amount of calcium in urine can help diagnose kidney problems and other conditions affecting calcium levels in your blood.
Activity 2: Fluid Intake and Urine Output Over 90 Minutes
Use the following items:
- o Same red cup (to collect urine) used in Activity 1.
- o Clear cup (to drink your favorite drink)
The same graduated cylinder used in Activity 1 to measure the volume of voided urine
Step 1: Drink Preparation
- Record your resting blood pressure at the beginning of this activity and enter the value in Table 3 and again at the end of the 90-minute period.
- Use the reference cup marked at 500 mL to create a 500 mL line on your own clear cup.
- Fill your cup with your favorite drink to reach 500 mL.
- Drink all of it within 2 minutes.
- Do not drink any other liquids during the 90-minute observation period.
- Discard the clear cup in the trash after use.
Step 2: Ongoing Urine Collection
- During the 90-minute period, record the parameters listed in Table 3 each time you urinate (at least once at the 90-minute mark if needed).
- Specific Gravity Measurement: Only one person per group should measure specific gravity using the refractometer.
- Use a pipette to place 2 dropsof urine on the glass.
- Close the plastic cover.
- Look through the eyepiece. Record where the white/blue line falls.
- Clean the glass and plastic cover using a pipette with distilled water. Dry when done.
- Return the refractometer to its case.
Table 3
| Time | 0 minutes | 30 minutes | 90 minutes |
| Volume | |||
| Color | |||
| Odor | |||
| Clarity | |||
| Specific Gravity
(measured by designated group member) |
|||
| Blood Pressure |
After each collection:
- Dispose of urine in the toilet.
- Wipe up any spills.
- Return cup to its paper towel pad at the edge of the lab, not on the lab tables.
- After collecting your final urine sample, discard the red collection cup in the biohazard bag.
Step 3: Graphing
Using Excel, create your own graph to analyze your data. Choose from the following options based on what you want to explore:
- Line Graph:
- Plot urine volume over time to visualize how fluid intake affects urine output.
- Plot specific gravity over time to observe changes in urine concentration.
- Bar Graph:
- Compare baseline vs. 90-minute values for specific gravity, urine volume, and blood pressure.
- This can help you identify trends or shifts caused by fluid intake.
- Before-and-After Comparison:
- Create a graph comparing blood pressure before drinking and after 90 minutes to examine whether fluid intake has a short-term effect on blood pressure.
Tip: Be sure to label your axes clearly and include a title that explains what your graph is showing.
Cleaning Instructions
When you have completed the lab:
- Thoroughly rinse both the 15 mL conical tube and the graduated cylinder with Alconox, followed by a rinse with water.
- Return the clean equipment to the designated table.
- Wipe down the urinalysis test results chart with disinfectant to prepare it for the next group.
This Week’s focus for the POPS Project Includes:
- Next week: POPS presentations! Please review the rubric to make sure your group is prepared to present the project and understands the expectations.
