How total cholesterol is calculated?

Cholesterol is a waxy, fatty substance that circulates in the blood, and this substance is called a lipid. Cholesterol is essential for maintaining the outer cell membrane, but excess cholesterol can cause health problems. Low-density lipoprotein (LDL) cholesterol is the "bad" cholesterol, and too much of it can lead to atherosclerosis. With this disease, the arteries are filled with fatty material that can cause heart attacks or strokes. Data released by the Centers for Disease Control and Prevention show that 73.5 million Americans, or 31.7% of the U.S. population, have high levels of LDL cholesterol. In order to understand how to keep your heart healthy, you must know how to calculate total cholesterol and what each indicator represents.

Note: There will be some test result values below, and their interpretation may vary from hospital to hospital and doctor to doctor. Please refer to the results from the hospital you visit and consult your doctor before making any conclusions about your test results.

Provide blood samples

1. Go to the hospital. Your doctor will perform a blood test to analyze blood proteins or lipoproteins and test your LDL, HDL and triglyceride levels, which combined will form a complete cholesterol reading.

LDL refers to low-density lipoprotein, which is actually a combined reading of LDL and very low-density lipoprotein (VLDL). Over time, LDL forms plaque in arteries, narrowing them and increasing the risk of heart disease, stroke, and other cardiovascular complications. They are often referred to as "bad" cholesterol.
HDL refers to high-density lipoproteins. HDLs transport cholesterol from the blood back to the liver, reducing the amount of cholesterol in the blood. This is why they are called "good" cholesterol.
Triglycerides are another type of fat molecule found in the blood that causes arteries to narrow and harden. As with LDL, high triglyceride levels increase the risk of cardiovascular disease and complications.

2. Fasting visits. In order to accurately measure the levels of the various components, you will need to fast for 9 to 12 hours prior to the blood draw. Because the test needs to measure an accurate minimum value, eating can raise the indicator and cause errors.

You can drink water before fasting.

3. Wait for the test results. The laboratory will do the appropriate tests on the blood sample and come up with the results. Your doctor will usually ask you to follow up a week after the blood is drawn to check the test results.

Interpreting the test results

1. Understand the indicators. The column for blood cholesterol concentration will show your cholesterol level. The number represents the number of milligrams of cholesterol per 1/10 of a liter of blood, and it is measured in mg/dL. The test report form may omit the units of the indicator, and the numbers represent the meaning as described above.

2. Evaluate LDL levels. Doctors usually consider that the ideal LDL level should be less than 100 mg/dL. for people without other medical conditions, the criteria for LDL levels are as follows.

Ideal - less than 100 mg/dL
Near optimal or slightly high - 100 to 129 mg/dL
High - 130 to 159 mg/dL
High - 160 to 189 mg/dL
Extremely high - above 190 mg/dL

3. Check the HDL level. A separate value will be included on the report card to show the HDL level. Doctors usually consider that the ideal HDL level should be equal to or higher than 60 mg/dL. For people without other medical conditions, the various criteria for HDL are as follows:

Ideal - not less than 60 mg/dL
Critical risk value for heart disease - 41 to 59 mg/dL
High risk value for heart disease - less than 40 mg/dL
HDL ranges for women are not given here. Women should review their test results or consult their physician to assess the normal range.

4. Evaluate triglyceride levels. Like high levels of LDL, high levels of triglycerides increase the risk of developing atherosclerosis, which narrows and hardens arteries, thereby increasing the risk of heart attack and stroke. If there is no other disease, then your doctor may consider a triglyceride level below 150 mg/dL to be ideal. The detailed criteria for triglyceride levels are as follows:[6]

Ideal - less than 150 mg/dL
High - 150 to 199 mg/dL
High - 200 to 499 mg/dL
Extremely high - above 500 mg/dL

5. Calculate the total cholesterol by substituting the values into the formula. Once you have the specific values for the three indicators, you can substitute them into a simple formula to calculate your own total cholesterol. The formula is:

LDL + HDL + (triglycerides/5) = total cholesterol.
For example, if your LDL level is 100, your HDL level is 60, and your triglyceride level is 150, the formula after substitution would be: 100 + 60 + (150/5).

6. Calculate total cholesterol. After substituting all values into the formula, the total cholesterol level can be calculated by simply dividing and adding the indicators for each component.

For example, in the previous example, 100 + 60 + (150/5) = 100 + 60 + 30 = 190.
You can also use an online calculator, which can calculate total cholesterol from the various values.

7. Evaluate total cholesterol levels. Similar to the individual component metrics, total cholesterol has a range of readings from ideal to higher values. If there are no other medical conditions, then your doctor will consider a total cholesterol level below 200 mg/dL to be ideal. The full range of readings is as follows.

Ideal - below 200 mg/dL
High - 200 to 239 mg/dL
High - 240 mg/dL or more

8. Ask your doctor to review your test results. Although total cholesterol is a useful indicator, you still need to ask your doctor to review the test results for each component, as total cholesterol can sometimes be somewhat misleading. For example, 99 LDL + 60 HDL + (200/5 triglycerides) = 199 total cholesterol. Although 199 is not yet an alarming total cholesterol level, 200 is high for triglycerides, so your doctor will still talk to you about various measures to control your triglyceride levels.

9. Take steps to lower your cholesterol. If any of the readings or total cholesterol levels are out of the optimal range, your doctor may recommend lifestyle changes to lower your cholesterol levels. These measures include.

Reducing saturated fats, trans fats, salt and sugar in your diet.
Choose healthy foods such as fruits, vegetables, legumes, whole grains and lean proteins.
Do at least thirty minutes of aerobic exercise each day.
Quit smoking (if you smoke).
Maintain a healthy weight.

A more convenient way to calculate total cholesterol

If you don't mind pricking your finger, you can have your cholesterol checked without sitting in a doctor's waiting room or lab. Devices available at pharmacies or on the Internet make this easy to do at home.

Products for home cholesterol testing are faster than going to the hospital to have your cholesterol checked. You prick your finger, gently squeeze a few drops of blood onto a test strip or into a small "well", and in a few minutes you'll have the results instead of waiting days.

One simple test gives you easy-to-understand results for the 3 key measurements of blood lipids: total cholesterol, HDL and triglycerides.