Cholesterol Test

What is the Normal Value of Blood Lipids? Cholesterol and Triglyceride Testing Instructions

Basic concepts of blood lipid testing

The human body uses cholesterol (Cholesterol) to build cells and produce hormones. However, if the concentration of cholesterol is too high, it will accumulate in the arteries and form fatty plaques, causing atherosclerosis.

Extensive atherosclerosis increases the risk of heart disease and stroke, so blood lipid testing, namely cholesterol and triglyceride testing, is needed to help analyze the blood.

Through blood lipid testing, we can check the concentration of cholesterol and triglycerides in the blood. Since cholesterol needs to be attached to proteins to form lipoproteins (Lipoprotein) in order to move in the blood and be used by cells and tissues, in addition to cholesterol and triglycerides Glycerolipid and cholesterol testing also includes low-density and high-density lipoprotein testing.

Routine cholesterol and triglyceride testing includes the following indicators:

High-density Lipoprotein

High-density Lipoprotein (HDL) can absorb fat and carry it to the liver for elimination, helping the body to remove fat. Therefore, HDL is also called “good cholesterol”. If the body contains more HDL , there will be a lower risk of heart disease.

Low-density lipoprotein

Low-density Lipoprotein (LDL) absorbs a lot of fat and a little protein from the liver to other parts of the body.

It is normal and healthy to have a certain amount of LDL in the body, because some parts of the body need the cholesterol carried by LDL. However, LDL is also called “bad cholesterol” because excessive low-density lipoprotein in the body will be deposited on the blood vessel walls to form Plaques, once these plaques rupture, the platelets will agglomerate and block the blood vessels, causing stroke or myocardial infarction.

In terms of cardiovascular risk, total cholesterol plays a more important role than triglycerides, and among cholesterol, low-density lipoprotein cholesterol is particularly harmful to cardiovascular disease. Therefore, it is recommended that if the public finds that LDL is too high, they should adjust their diet and improve bad habits such as smoking as soon as possible to prevent the continued accumulation of fatty plaques in the cardiovascular system. (Recommended reading: There is no worst, only worse! Cholesterol becomes bad, and lipoproteins are responsible!)

Total cholesterol

Total cholesterol (TC) refers to the total amount of lipoprotein cholesterol and free cholesterol (unlipidated cholesterol), which is the total cholesterol in the human body.

High cholesterol may put a patient at higher risk for cardiovascular disease. In addition, the ratio of total cholesterol to high-density lipoprotein (TC/HDL-C) can also be used to diagnose atherosclerosis in patients. The higher the ratio, the greater the patient’s risk of cardiovascular disease.


Triglyceride (TG) is a neutral fat that the body uses to store energy or produce energy needed by muscles. If both triglycerides and LDL are too high, the risk of heart disease is also higher than if LDL alone is too high.

Why do you need a cholesterol and triglyceride test?

It is actually very important to check cholesterol or triglycerides regularly, because dyslipidemia often does not have obvious symptoms, and if there is no regular health check-up, it is easy to ignore the warning signs they provide. It is generally recommended to check blood lipids every 4 to 6 years.

Since the older you get, the higher your risk of cardiovascular disease due to blood lipids, the National Health Service of the provides adult health examinations including cholesterol and triglyceride tests. This may because of your age, weight or another condition you have (like high blood pressure or diabetes). Ask your GP surgery for a cholesterol test if: you have not had a test before and you’re over 40, overweight, or high cholesterol or heart problems run in your family.

Not only healthy adults, but also diabetic patients should regularly check their triglyceride index. If blood sugar is not well controlled, the triglyceride index will increase.

In addition, children may also have high cholesterol. In view of the increasing proportion of childhood obesity year by year, the American Academy of Pediatrics recommends that all children should have their blood cholesterol tested between the ages of 9 and 11.

In addition, if the child’s family has a history of premature cardiovascular disease (for example, a male has an early stroke or myocardial infarction before the age of 55 or a female has a myocardial infarction before the age of 65), or even if the child’s parents or grandparents have blood cholesterol ≥240 mg/dl, and if the child If you have heart disease or have risk factors that increase heart disease, such as a history of diabetes, high blood pressure, or being overweight, it is recommended that children’s blood cholesterol screening should be done as early as two years old and no later than 10 years old. If the result If it is normal, follow-up inspections will be conducted every 3 to 5 years.

Do cholesterol and triglycerides need to be checked on an empty stomach?

Generally speaking, blood lipid tests almost always include triglycerides, so you still need to take a blood test on an empty stomach. But did you know that fasting does not actually have much impact on cholesterol values, and the main thing is that triglycerides will change significantly. ?

After the human body eats, food will be broken down in the intestines to produce chylomicrons. Its main function is to transport triglycerides to various tissues for use, and it contains only a small amount of cholesterol.

The main source of cholesterol in the human body is produced by the liver (about 70%), rather than from food (about 30%), so fasting is actually to avoid changes in triglyceride concentration caused by food, which will affect the test results!

However, many scholars are now beginning to study triglyceride levels in non-fasting people. This is because daily blood lipid levels mainly reflect postprandial levels rather than fasting levels. Therefore, non-fasting samples may be more representative of “usual” levels. Circulating levels of triglycerides.

Having said that, before taking a blood lipid test, it is best for people to ask their doctor whether fasting is necessary and follow the doctor’s advice.

What should I know about the blood lipid testing process and what preparations should I make in advance?
Depending on the test you undergo, there will be different preparation items:

  1. If the doctor instructs you to fast before the test, please stop eating and drinking at least eight hours before blood drawing, and only drink water and do not take any medicine.
  2. Do not eat high-fat foods the night before the test.
  3. Do not drink alcohol or do high-intensity exercise before the test.

Many drugs may affect test results, such as corticosteroids, Protease Inhibitors for HIV, Beta Blockers, and Estrogens. It can affect total cholesterol, triglycerides, high-density lipoprotein, or low-density lipoprotein in the blood, so be sure to tell your doctor about the medications you are taking.

In addition, if you have had a radioactive test within a week, such as a thyroid or bone scan, please inform your doctor. If you have any doubts about the test, please also ask your doctor to evaluate the risks, process, results explanation, etc. of the test.

What are the steps for blood lipid testing?

The blood drawing process to test triglycerides and cholesterol is as follows:

  1. The tester will wrap an elastic band around the upper arm to block blood flow. This will make the blood vessels distal to the elastic band larger, making it easier to insert the needle into the blood vessels.
  2. Sterilize the needle with alcohol.
  3. Insert the needle into the blood vessel. More than one needle may be needed.
  4. Connect the tube to the needle and let the blood flow into the tube.
  5. After enough blood has been drawn, the testing staff will remove the elastic band from the arm.
  6. After removing the needle, the testing staff will provide a cotton ball and ask you to press it on the injection site to stop the bleeding or apply tape to fix it.

Post-test instructions

The bandage and cotton can be removed 20 to 30 minutes after the test, and you can make an appointment with the doctor to learn about the test results. The doctor will also explain and analyze in detail. Please follow the doctor’s instructions. If you have any questions about cholesterol and triglyceride tests, If you have any concerns, please consult your physician for more information.

Blood lipid test results

Different clinics and hospitals may have different definitions of common ranges for cholesterol and triglyceride testing. If you have any questions about the test results, please consult your physician.

blood test tube on the results

What is the normal value of blood lipids?

The general cholesterol and triglyceride standards for adults are as follows:

Acute symptoms of high triglycerides

Although it was mentioned earlier that in most cases, we will not have acute symptoms due to changes in blood lipids, there are exceptions. For example, acute pancreatitis (or pancreatitis) may be caused by an excessively high triglyceride index (>500 mg/dl). The patient’s blood may be chylous and the serum color may be milky white, and treatment should be carried out as soon as possible. The condition of excessive triglycerides is also commonly known as blood oil or blood turbidity.

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