Fasting cholesterol check

Cholesterol test - Mayo Clinic

Overview

A complete cholesterol test — also called a lipid panel or lipid profile — is a blood test that can measure the amount of cholesterol and triglycerides in your blood.

A cholesterol test can help determine your risk of the buildup of fatty deposits (plaques) in your arteries that can lead to narrowed or blocked arteries throughout your body (atherosclerosis).

A cholesterol test is an important tool. High cholesterol levels often are a significant risk factor for coronary artery disease.

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Why it's done

High cholesterol usually causes no signs or symptoms. A complete cholesterol test is done to determine whether your cholesterol is high and to estimate your risk of heart attacks and other forms of heart disease and diseases of the blood vessels.

A complete cholesterol test includes the calculation of four types of fats in your blood:

Total cholesterol. This is a sum of your blood's cholesterol content.
Low-density lipoprotein (LDL) cholesterol. This is called the "bad" cholesterol. Too much of it in your blood causes the buildup of fatty deposits (plaques) in your arteries (atherosclerosis), which reduces blood flow. These plaques sometimes rupture and can lead to a heart attack or stroke.
High-density lipoprotein (HDL) cholesterol. This is called the "good" cholesterol because it helps carry away LDL cholesterol, thus keeping arteries open and your blood flowing more freely.
Triglycerides. Triglycerides are a type of fat in the blood. When you eat, your body converts calories it doesn't need into triglycerides, which are stored in fat cells. High triglyceride levels are associated with several factors, including being overweight, eating too many sweets or drinking too much alcohol, smoking, being sedentary, or having diabetes with elevated blood sugar levels.

Who should get a cholesterol test?

According to the National Heart, Lung and Blood Institute (NHLBI), a person's first cholesterol screening should occur between the ages of 9 and 11 and then be repeated every five years after that.

The NHLBI recommends that cholesterol screenings occur every 1 to 2 years for men ages 45 to 65 and for women ages 55 to 65. People over 65 should receive cholesterol tests annually.

More-frequent testing might be needed if your initial test results were abnormal or if you already have coronary artery disease, you're taking cholesterol-lowering medications or you're at higher risk of coronary artery disease because you:

Have a family history of high cholesterol or heart attacks
Are overweight
Are physically inactive
Have diabetes
Eat an unhealthy diet
Smoke cigarettes

People undergoing treatment for high cholesterol require regular cholesterol testing to monitor the effectiveness of their treatments.

More Information

Blood tests for heart disease
Childhood obesity
Obesity
Polycystic ovary syndrome (PCOS)
Transient ischemic attack (TIA)

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Risks

There's little risk in getting a cholesterol test. You might have soreness or tenderness around the site where your blood is drawn. Rarely, the site can become infected.

How you prepare

You're generally required to fast, consuming no food or liquids other than water, for nine to 12 hours before the test. Some cholesterol tests don't require fasting, so follow your doctor's instructions.

What you can expect

During the procedure

A cholesterol test is a blood test, usually done in the morning if you fast overnight. Blood is drawn from a vein, usually from your arm.

Before the needle is inserted, the puncture site is cleaned with antiseptic and an elastic band is wrapped around your upper arm. This causes the veins in your arm to fill with blood.

After the needle is inserted, a small amount of blood is collected into a vial or syringe. The band is then removed to restore circulation, and blood continues to flow into the vial. Once enough blood is collected, the needle is removed and the puncture site is covered with a bandage.

The procedure will likely take a couple of minutes. It's relatively painless.

After the procedure

There are no precautions you need to take after your cholesterol test. You should be able to drive yourself home and do all your normal activities. If you've been fasting, you might want to bring a snack to eat after your cholesterol test is done.

Results

In the United States, cholesterol levels are measured in milligrams (mg) of cholesterol per deciliter (dL) of blood. In Canada and many European countries, cholesterol levels are measured in millimoles per liter (mmol/L). To interpret your test results, use these general guidelines.

Total cholesterol(U.S. and some other countries)	Total cholesterol*(Canada and most of Europe)
Below 200 mg/dL	Below 5. 18 mmol/L	Desirable
200-239 mg/dL	5.18-6.18 mmol/L	Borderline high
240 mg/dL and above	Above 6.18 mmol/L	High

LDL cholesterol(U.S. and some other countries)	LDL cholesterol*(Canada and most of Europe)
Below 70 mg/dL	Below 1.8 mmol/L	Best for people who have coronary artery disease — including a history of heart attacks, angina, stents or coronary bypass.
Below 100 mg/dL	Below 2.6 mmol/L	Optimal for people at risk of coronary artery disease or who have a history of diabetes. Near optimal for people with uncomplicated coronary artery disease.
100-129 mg/dL	2.6-3.3 mmol/L	Near optimal if there is no coronary artery disease. High if there is coronary artery disease.
130-159 mg/dL	3.4-4.1 mmol/L	Borderline high if there is no coronary artery disease. High if there is coronary artery disease.
160-189 mg/dL	4. 1-4.9 mmol/L	High if there is no coronary artery disease. Very high if there is coronary artery disease.
190 mg/dL and above	Above 4.9 mmol/L	Very high.

HDL cholesterol(U.S. and some other countries)	HDL cholesterol*(Canada and most of Europe)
Below 40 mg/dL, men Below 50 mg/dL, women	Below 1 mmol/L, men Below 1. 3 mmol/L, women	Poor
40-59 mg/dL, men 50-59 mg/dL, women	1-1.5 mmol/L, men 1.3-1.5 mmol/L, women	Better
60 mg/dL and above	Above 1.5 mmol/L	Best

Triglycerides(U.S. and some other countries)	Triglycerides*(Canada and most of Europe)
Below 150 mg/dL	Below 1. 7 mmol/L	Desirable
150-199 mg/dL	1.7-2.2 mmol/L	Borderline high
200-499 mg/dL	2.3-5.6 mmol/L	High
500 mg/dL and above	Above 5.6 mmol/L	Very high

*Canadian and European guidelines differ slightly from U.S. guidelines. These conversions are based on U.S. guidelines.

If your results show that your cholesterol level is high, don't get discouraged. You might be able to lower your cholesterol with lifestyle changes, such as quitting smoking, exercising and eating a healthy diet.

If lifestyle changes aren't enough, cholesterol-lowering medications also might help. Talk to your doctor about the best way for you to lower your cholesterol.

By Mayo Clinic Staff

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Fasting Before a Cholesterol Test: Should You Do It?

Overview

Cholesterol is a fatty material that’s produced by your body and found in certain foods. While your body needs some cholesterol in order to function properly, having too much, or high cholesterol, raises your risk of a heart attack or stroke.

Because of this risk, knowing your cholesterol levels is an important part of good heart health. The American Heart Association (AHA) recommends that adults have a cholesterol test every four to six years, starting at age 20.

People with known high cholesterol levels or other chronic health conditions should get tested more often.

To prepare for a cholesterol test, you may have heard that you should fast, or avoid eating. But is fasting really necessary? The answer is maybe.

The truth is, your cholesterol can be tested without fasting. In the past, experts believed fasting ahead of time produces the most accurate results. This is because your low-density lipoproteins (LDL) — also known as “bad” cholesterol — may be affected by what you’ve recently eaten. Your levels of triglycerides (another type of fat in your blood) may also be affected by a recent meal.

New guidelines, published in the Journal of the American College of Cardiology, say that people who aren’t taking statins may not need to fast before having their blood tested for cholesterol levels.

Your doctor may recommend fasting before having your cholesterol checked. If they say you should fast, they’ll likely suggest that you avoid eating for 9 to 12 hours before your test.

For this reason, cholesterol tests are often scheduled in the morning. That way, you don’t have to spend a whole day hungry while waiting to have your test.

Cholesterol is measured using a blood test. A healthcare provider will draw your blood using a needle and collect it in a vial. This typically takes place at your doctor’s office or at a lab where the blood is then analyzed.

The test only takes a couple of minutes and is relatively painless. However, you might have some soreness or bruising on your arm around the injection site.

Your results will likely be available in a few days or within a couple of weeks.

If you aren’t already taking cholesterol medications, it may not be necessary to fast.

Depending on your situation, your doctor might recommend drinking only water and avoiding food, other drinks, and certain medications in order to make sure your results are accurate.

What else should you avoid? Alcohol. Drinking within 24 hours before your test can affect your triglyceride levels.

Your blood will likely be checked using a test called a total lipid profile. To understand your cholesterol test results, you’ll need to know the different types of cholesterol that the test measures and what’s considered normal, potentially risky, and high.

Here’s a breakdown of each type. Keep in mind that people who have conditions such as diabetes may need to aim for even lower numbers.

Total cholesterol

Your total cholesterol number is the overall amount of cholesterol found in your blood.

Acceptable: Below 200 mg/dL (milligrams per deciliter)
Borderline: 200 to 239 mg/dL
High: 240 mg/dL or higher

Low-density lipoprotein (LDL)

LDL is the cholesterol that blocks your blood vessels and increases your risk of heart disease.

Acceptable: Below 70 if coronary artery disease is present
Below 100 mg/dL if at risk for coronary artery disease or have a history of diabetes
Borderline: 130 to 159 mg/dL
High: 160 mg/dL or higher
Very high: 190 mg/dL and above

High-density lipoprotein (HDL)

HDL is also called good cholesterol and helps protect you from heart disease. This type removes excess cholesterol from your blood, helping to prevent buildup. The higher your HDL levels are, the better.

Acceptable: 40 mg/dL or higher for men and 50 mg/dL or higher for women
Low: 39 mg/dL or lower for men and 49 mg/dL or lower for women
Ideal: 60 mg/dL or higher

Triglycerides

High triglyceride levels coupled with high levels of LDL raise your risk for heart disease.

Acceptable: 149 mg/dL or lower
Borderline: 150 to 199 mg/dL
High: 200 mg/dL or higher
Very high: 500 mg/dL and higher

You want your cholesterol test results to fall within the acceptable ranges. If your numbers are in the borderline or high levels, you’ll need to make some lifestyle changes and may need to take medication such as a statin. Your doctor may also want to check your levels more often.

Getting your cholesterol levels tested is an important part of keeping your heart and blood vessels healthy. In general, fasting before your test isn’t required. But your doctor may recommend fasting if you’re already taking a cholesterol medication.

Be sure to ask your doctor before your test whether you need to fast.

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Description

Method of determination Enzymatic (CHOD-PAP).

Test material Blood serum

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Synonyms: Cholesterol, cholesterol. Blood cholesterol, Cholesterol, Chol, Cholesterol total.

Brief description of the analyte Total cholesterol

About 80% of all cholesterol is synthesized by the human body (liver, intestines, kidneys, adrenal glands, gonads), the remaining 20% comes from food of animal origin (meat, butter, eggs). Cholesterol is insoluble in water; it is transported in the blood in lipoprotein complexes. There are fractions of high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), very-low-density lipoprotein cholesterol (VLDL), and some others that differ in composition and function. Total cholesterol includes cholesterol contained in all types of circulating lipoproteins, esterified and free.

The content of cholesterol in the blood depends to a large extent on age. Its level at birth is less than 3.0 mmol / l, then gradually increases. Emerging differences in its concentration are associated with gender. In men, the concentration of cholesterol in the blood increases in early and middle age and decreases in old age. In women, cholesterol levels increase more slowly with age, up to menopause; in the future may exceed cholesterol levels in men. The described age-related changes in the content of cholesterol in the blood are associated with the action of sex hormones: estrogens reduce, and androgens increase the level of total cholesterol. During pregnancy, there is a physiological increase in total cholesterol levels.

Determination of cholesterol is mainly used to assess the risk of developing atherosclerosis and in the diagnosis of any kind of lipid metabolism disorders. It has been established that elevated blood cholesterol levels contribute to the development of vascular atherosclerosis and coronary heart disease. The level of total cholesterol in combination with data on existing diseases, age, gender, blood pressure, the fact of smoking, is taken into account when assessing the individual risk of developing severe complications of cardiovascular diseases (myocardial infarction or stroke) according to the SCORE (Systematic COronary Risk Evaluation) scale. It is advisable to investigate cholesterol in combination with the determination of triglycerides (see test No. 30), HDL cholesterol (see Test No. 32), the calculation of non-HDL cholesterol (see Test No. NHDL) and LDL cholesterol (see Test No. 33), since For a correct assessment of cardiovascular risks, it is important to understand the ratio of different fractions of lipoproteins. Thus, high HDL cholesterol indicates a low risk, and the detection of an increased concentration of triglycerides, in combination with a decrease in HDL, makes it possible to suspect certain pathological conditions (including metabolic syndrome, insulin resistance), which are themselves associated with increased cardiovascular risk.

What is the purpose of determining the level of total cholesterol in the blood? . To reduce the risk of complications of cardiovascular diseases, it is recommended to maintain the concentration of total cholesterol in the blood below 5.0 mmol / l. The therapeutic goal of lipid-lowering therapy is to lower LDL cholesterol levels.

Disorders of cholesterol metabolism, accompanied by an increase in its content in the blood, are characteristic of hypothyroidism. Secondary hypercholesterolemia is also observed in hepatic cholestasis, nephrotic syndrome, chronic renal failure, gout, diabetes and other diseases. Before starting therapy with lipid-lowering drugs, diseases that lead to an increase in cholesterol levels should be excluded.

Cholesterol level reflects the activity of synthesis processes in the liver. In severe liver damage, there is a significant decrease in the concentration of cholesterol in the blood. Acute tissue injury also causes a marked drop in total and LDL cholesterol levels. It begins within the first day after a heart attack, surgery or septicemia and can reach a 40% reduction from baseline. Lipid levels do not return to normal for up to three months. Therefore, a lipid study to assess the risk of atherosclerosis should not be performed within three months after acute conditions.

More details about the laboratory assessment of lipid metabolism parameters can be found here.

Preparation

Rules for preparation for the study Cholesterol total

Strictly on an empty stomach, after a night fasting period of 8 to 14 hours. On the eve of the study, it is necessary to exclude increased psycho-emotional and physical activity (sports training), alcohol intake.

Indications for prescription

In what cases is a blood test for Cholesterol total

Assessment of the risk of developing cardiovascular diseases and their complications using the SCORE scale.
Determining the type of dyslipidemia.
The choice of therapeutic tactics.
As part of biochemical profiles to assess metabolic changes in a patient.

Interpretation of results

Interpretation of test results contains information for the attending physician and is not a diagnosis. The information in this section should not be used for self-diagnosis or self-treatment. An accurate diagnosis is made by the doctor, using both the results of this examination and the necessary information from other sources: history, results of other examinations, etc.

Interpretation of the results of the study on total cholesterol in the blood

Units of measurement: mmol / l.
Alternate units: mg/dl.
Unit conversion: mg/dL x 0.026 ==> mmol/L.

Adults. Desirable level <5.0 mmol/L. In accordance with the clinical recommendations of European and Russian medical communities, the level of total cholesterol in the assessment of the risk of cardiovascular diseases should be used in combination with other individual factors using the SCORE assessment scale, including additional correction of potential risk taking into account HDL cholesterol values.

Reference values  (population spread) concentration of total cholesterol for children and adolescents, mmol/l:

2.90 - 5.18
5 - 10 years	3.13 - 5.25	2.26 - 5.30
10 - 15 years	3.08 - 5 - 5 - 5 - 5 - 5 - 5 - 5 - 5 .23	3.21 - 5.20
15 - 18 years old	2.93 - 5.10	3.08 - 5.18

Data on the population dispersion of total cholesterol values in adults -

, see here.

Increased levels (hypercholesterolemia)

Primary hyperlipidemias:

Familial or polygenic hyperlipoproteinemia (types IIA, IIB), familial dys-beta-lipoproteinemia (type I, IV, III), familial hyperlipidemia V and hyper-alpha-lipoproteinemia.
Deficiency of acid lysosomal lipase (rare hereditary fermentopathy).

Secondary hyperlipidemias:

Liver diseases, intra- and extrahepatic cholestasis.
Glomerulonephritis, nephrotic syndrome, chronic renal failure.
Malignant tumors of the pancreas and prostate.
Hypothyroidism.
Gout.
Ischemic heart disease.
Diabetes mellitus.
Pregnancy.
Alcoholism.
Isolated somatotropic hormone (GH) deficiency.
Food rich in cholesterol and unsaturated fatty acids.
Use of drugs such as androgens, cyclosporine, diuretics, ergocalciferol (high doses), glucocorticosteroids, levodopa, amiodarone.

Decreased level (hypocholesterolemia)

Cachexia, starvation.
Malabsorption syndrome.
Major burns.
Severe acute diseases and infections.
Hepatocyte necrosis, end-stage liver cirrhosis, hepatocarcinoma.
Sepsis.
Hyperthyroidism.
Hypo-alpha- and beta-lipoproteinemia.
α-lipoprotein deficiency.
Megaloblastic anemia.
Thalassemia.
Chronic obstructive pulmonary disease.
Rheumatoid arthritis.
Intestinal lymphangiectasia.
Taking cholesterol-lowering drugs.
Taking certain medications (clomiphene, estrogen, interferon, neomycin, thyroxine, ketoconazole).
Food low in cholesterol and high in polyunsaturated acids.

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In this section, you can find out how much it costs to complete this study in your city, read the description of the test and the table for interpreting the results. When choosing where to take the analysis "Cholesterol total (cholesterol, Cholesterol total)" in Moscow and other cities of Russia, do not forget that the price of the analysis, the cost of the procedure for taking biomaterial, methods and terms for performing studies in regional medical offices may differ.

How to prepare for a cholesterol test, and how is it decoded?

24 Nov 2019

14 Sep 2020

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Contents

Why do a blood test?
How to prepare?
Blood test
Explanation of results

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How to prepare for a cholesterol test, and how is it deciphered?

Controlling cholesterol levels is an important condition for maintaining health, especially in old age. Elevated levels significantly increase the risk of atherosclerotic plaque formation, which can lead to stroke and heart attack. To know your cholesterol level, you need to take a blood test.

Why take a blood test?

Lipidogram allows not only to detect the presence of excess cholesterol in the blood, but also to calculate the balance between bad and good substances. Cholesterol belongs to fatty alcohols and is essential for cell elasticity in the body. If its amount becomes higher than normal, there is a risk of complications. It is especially dangerous when the balance between high and low density lipoproteins is disturbed.

Attention! The general norm of cholesterol in a biochemical blood test should not exceed 5 mmol / liter. In children, the rate is even lower -4.5 mmol / liter

How to prepare?

There are rules, subject to which a reliable blood test will be obtained, which will accurately show the level of lipoproteins in the blood:

The test must be taken on an empty stomach. For this, it is better not to eat for 12-16 hours. Most often, blood biochemistry is taken in the morning so that the patient has time to undergo the procedure before breakfast.
Fatty foods are not recommended for two days prior to analysis.
Alcohol must be stopped within a day.
Do not smoke for 2 hours.
The day before blood donation, all juices and any fruit drinks must be excluded from the diet. It is better to drink only non-carbonated water.
All medications should be discontinued and if needed, notify the physician.
It is imperative to rest after any physical activity for at least 15 minutes.

Attention! If specialists do not need exact indicators, but averages, then you can not specially prepare for the analysis procedure. In this case, average cholesterol values are obtained.

Blood donation for analysis

To begin with, the patient is sent for a general blood test. If it detects indicators above 5.2 mmol / liter, a separate biochemical analysis is prescribed to identify the exact amount of lipids of different densities (lipidogram).

Waste lipids are contained in venous blood, and therefore it is taken for research. Another reason for taking blood from a vein is quantity. For a blood lipid profile, a little more biomaterial is needed than doctors receive when sampling from the soft tissues of a finger.

When examining biomaterial for cholesterol levels, several different methods are used:

Gravimetry. With this method, the mass of the investigated component is measured.
Nephelometry. A luminous flux is used, which is scattered in an opaque medium.
Chromatography. Helps to study the movement of small particles in a moving and stationary medium.
Titration. A chemical method based on the calculation of the reacted reagent with a certain substance.
Polarography. The study is carried out on the amount of total and free cholesterol in the presence of enzymes.
Examination using ultraviolet (fluorimetry).
Color reactions.

Which specific research method is used also depends on the qualifications of the laboratory assistant.

Interpretation of results

After receiving the analysis, you need to pay attention to 2 important indicators:

HDL alpha-cholesterol. This is the “good” cholesterol that the body needs. It enters the liver and is not deposited on the walls of blood vessels. Its norm can be 1 mmol / liter or more.
LDL. Harmful cholesterol, the content of which should not exceed 3 mmol/liter. Otherwise, it accumulates on the walls of blood vessels and forms atherosclerotic plaques that can cause heart and brain diseases.