Materials Included In Kit

Additional Materials Required

Prelab Preparation

Materials can be organized by stations and blood samples can be dispensed into the microcentrifuge tubes prior to classroom work.

Safety Precautions

There are no real blood or blood products in the materials in this simulation. Treat the materials as laboratory chemicals. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Please review current Safety Data Sheets for additional safety, handling and disposal information.

Disposal

Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. All materials can be disposed of according to Flinn Suggested Disposal Method #26b.

Teacher Tips

• Enough materials are provided in this kit for 30 students working in pairs or for 15 groups of students. The laboratory activity can reasonably be completed in one 50-minute class period.

• This is a simulated cholesterol test. The strips in this kit cannot be used to test real blood for cholesterol.
• The cholesterol tests performed in this simulated lab exercise use no blood products. The simulated blood contains various concentrations of glucose and the blood is tested for “cholesterol” by using glucose test strips to measure the concentration of “cholesterol.” Students use the glucose test strips along with the Cholesterol Comparitor Cards when they do their tests. The glucose test strips should be kept in the bottle until class use and students need not know that they are actually testing for glucose in the simulation.

Sample Data

Part I. Initial Testing

Part II. Post-Treatment Testing

Answers to Questions

1. Did any person experience an increase in cholesterol level after treatment? What might account for this?
   

   Person 1 has an increase in cholesterol level and is probably a normal fluctuation in blood cholesterol level.
   

2. Which individual had the most improvement in their cholesterol level? What probably also decreased for this person?
   

   Person 4 showed the most improvement. The person probably lost weight along with the reduced cholesterol.
   

3. What might be the reason that Person 5 did not reduce their cholesterol even after following a good dietary routine?
   

   The person probably has a genetic predisposition for high cholesterol.

Introduction

Cholesterol is a paradox: Everyone needs it, but too much of this good thing can spell trouble for some people. Learn more about the issues related to cholesterol and simulate a blood test for cholesterol.

Concepts

• Total cholesterol

• HDL cholesterol
• Lipoproteins
• LDL cholesterol
• Triglycerides

Background

Cholesterol is a waxy, fat-like substance found in foods of animal origin and can be found in every body cell. It is essential for human life. It helps in the building and repair of cells. It is also an integral part of the chemical pathway producing the sex hormones—estrogen and testosterone. Cholesterol is converted to bile acids to help digest food and cholesterol is found in large amounts in the brain and nerve tissue.

Normally your liver makes all of the cholesterol your body needs. Concerns about cholesterol usually arise when dietary habits include too much cholesterol. Foods like meat, especially organ meats such as liver and kidney, eggs and other dairy products can rapidly increase one’s cholesterol intake. Cholesterol is not found in plant foods like fruits, vegetables or vegetable oils. While foods derived from plant products do not contain cholesterol, they can (like animal products) contain saturated fats. A diet high in saturated fat can also raise your cholesterol level, especially if there is a genetic predisposition to high cholesterol.

The cholesterol and fats that are eaten are absorbed into the bloodstream through the intestines. Much of the fat is transported to fat cells while most of the cholesterol is taken to wherever your body needs it. Cholesterol doesn’t float easily in the water-based blood stream. Instead, it is transported in special protein packages called lipoproteins. A typical lipoprotein contains triglycerides (another type of blood fat) and cholesterol in the center, surrounded by phospholipids and water-soluble proteins on the outer surface to help the lipids move through the blood. The various types of lipoproteins differ from one another in their content of protein, triglycerides and cholesterol. Two types of lipoproteins are of special interest to people concerned with their cholesterol health—HDL cholesterol and LDL cholesterol.

HDL cholesterol (High-density Lipoproteins) is commonly known as the “good” cholesterol because high concentrations in the blood are associated with a low risk of heart attack. HDL contains more protein than triglycerides or cholesterol and helps remove cholesterol from artery walls. HDL carries cholesterol from body cells to the liver, either to be reused, converted to bile acids or disposed of in the bile.

LDL cholesterol (Low-density Lipoproteins) is known as the “bad” cholesterol because it is associated with a higher risk of heart disease. LDL becomes oxidized and deposits on the inner walls of the arteries to initiate a condition known as “atherosclerosis” or hardening of the arteries.

It is not clear whether high triglycerides alone increase the risk of heart disease, but many people with high triglycerides also have high LDL and low HDL levels. Blood tests for cholesterol usually include readings for total cholesterol, HDL, LDL and triglycerides.

The numbers from cholesterol tests provide doctors with a profile of the potential risks of the person being tested. A person with high cholesterol may not ever have heart disease and a person with low cholesterol may have heart disease, but the test numbers have proven to be a good indication of potential risks. There is some variation in the acceptable levels of these various components, but most medical experts use the following guidelines:

Triglyceride levels less than 150 are optimal.

If the total cholesterol level is over 200 mg/dL (considered high to borderline for an average adult), it may be lowered through change in diet by eating fewer saturated (animal) fats and eating more unsaturated (plant) fats. It also appears that cholesterol levels can be positively reduced by regular exercise. Often proper diet and exercise do not reduce cholesterol levels due to the influence of genetics. Certain genetic disorders or tendencies can determine that an individual’s cholesterol level is high. If the total cholesterol level is over 240 mg/dL, doctors will recommend cholesterol-lowering drugs in the hope of slowing the premature development of atherosclerosis.

Cholesterol testing is done with a simple blood test and the levels of the various components are reported to the physician. Depending upon the total cholesterol level and the ratio of LDL/HDL, the physician will prescribe a personal course of action or maintenance. It is very important to develop good habits at a young age to help reduce future risks.

The American Heart Association has offered guidelines for healthy adult Americans to include the following:

• Saturated fat should be less than 7–10% of total calories.
• Total fat calories should be less than 30% of total calories.
• Cholesterol intake should not exceed 300 mg daily (i.e., less than 100 mg per 1,000 calories).
• Protein calories should be 15% of total calories daily.
• Carbohydrate calories should be 55% or more of total calories.
• Sodium intake should be limited to less than 3 g daily.
• Alcohol consumption should be less than 15% total calories.
• Total calories consumed should maintain a constant body weight and a wide variety of foods should be consumed.

Materials

Safety Precautions

There are no real blood products in the simulated blood in this laboratory. Treat all materials as regular laboratory chemicals. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Wash hands before leaving the laboratory.

Procedure

Part I. Initial Testing

1. Label five microcentrifuge tubes 1–5.
2. Place 0.5 mL of simulated blood from Person 1 into microcentrifuge tube 1. Place 0.5 mL of simulated blood from persons 2–5 into respective microcentrifuge tubes 2–5.
3. Dip a Cholesterol Test Strip into microcentrifuge tube 1 so that the top of the strip is completely submerged in the sample. Let it soak for four seconds.
4. Remove the test strip from the simulated blood. Dab off excess solution using a paper towel.
5. Watch for a color change in the strip indicator pad. It will turn various colors depending upon the amount of cholesterol in the blood sample.
6. After exactly 30 seconds, compare the color to the colors on the Cholesterol Comparator Chart.
7. Record the corresponding cholesterol level on the Cholesterol Worksheet for Person 1 initial testing.
8. Repeat steps 3–6 for the remaining people 2–5 and record the results on the Cholesterol Worksheet.
9. Discuss the results for each individual and fill in the Risk Level.
10. Suggest a treatment strategy for each individual and record it on the Cholesterol Worksheet.

Part II. Post-Treatment Testing

Assume that the five people have followed your treatment suggestions. It is now six months later and they are to be retested for their cholesterol level.

11. Label five microcentrifuge tubes 1–5B.
12. Repeat steps 2–6.
13. Record the test results in the appropriate spaces on the Cholesterol Worksheet and complete the remainder of the Part II chart for each individual.
14. Answer the questions on the worksheet.
15. Consult your instructor for appropriate disposal procedures.

Student Worksheet PDF

10449_Student1.pdf