High cholesterol in the blood leads to the formation of atherosclerotic plaques on the vascular walls. Over time, these structures can clog the artery, which often ends with the development of a stroke or heart attack.
Therefore, everyone should know what serum cholesterol is considered normal. To determine the level of cholesterol, you can use various laboratory tests.
To decipher the results of the study, you must first understand what cholesterol is. It is also important to know the rate of fatty alcohol in the blood.
What is cholesterol, and why does it go up
Cholesterol is a monohydric fatty alcohol. The substance is part of the cell membrane, it participates in the production of steroid hormones, promotes the synthesis of bile acids and vitamin D.
Cholesterol is present in all body fluids and tissues in a free state or as ethers with fatty acids. Its production occurs in every cell. The leading transport forms in the blood are low and high density lipoproteins.
Cholesterol in the blood plasma is contained in the form of esters (up to 70%). The latter are formed in the cells as a result of a special reaction or in the plasma as a result of the work of a specific enzyme.
For human health, it is low-density lipoproteins that are dangerous. The causes of their increased accumulation in the blood can be changeable and unchangeable.
The leading factor leading to an increase in cholesterol indicators is not a healthy lifestyle, in particular, poor diet (regular consumption of fatty animal food), alcoholism, smoking, lack of physical activity. Even adverse changes in the environment can also raise the level of LDL in the blood.
Another reason for the development of hypercholesterolemia is overweight, which is often accompanied not only by a violation of lipid metabolism, but also by carbohydrate, when a person’s blood glucose concentration rises. All this often leads to the onset of type 2 diabetes.
A constant factor that causes an increase in the concentration of cholesterol in the blood is genetic predisposition and age.
In advanced cases, hypercholesterolemia will have to be treated for life. In this case, the patient will need to constantly follow a special diet and take statins.
In order to prevent the development of atherosclerosis, heart attack and stroke, you should promptly pay attention to a number of symptoms that may indicate an elevated level of cholesterol. Leading signs of lipid metabolism disorders:
- The formation of yellow spots on the skin near the eyes. Often, xanthoma is formed by genetic predisposition.
- Angina pectoris due to constriction of the cardiac coronary arteries.
- Pain in the limbs during physical activity. This symptom is also a consequence of the narrowing of the vessels supplying blood to the arms and legs.
- Heart failure that develops due to nutrient deficiencies in oxygen.
- Stroke that occurs due to the tearing of atherosclerotic plaques from the vascular walls, which leads to the formation of a blood clot.
Often, cholesterol levels are elevated in people suffering from a number of specific diseases. Thus, hypercholesterolemia often accompanies diabetes mellitus and other pancreatic pathologies, hypothyroidism, diseases of the liver, kidneys, and heart.
Such patients are always at risk, so they should periodically check the level of cholesterol in the blood and know its rate.
Serum cholesterol levels can vary depending on age, gender and general condition of the body. But doctors say that the permissible limits should not exceed 5.2 mmol / l. However, even if the level of cholesterol is 5.0 mmol / l, this does not mean that the patient has not disturbed lipid metabolism, because the concentration of total cholesterol does not give accurate information.
The normal content of cholesterol in the blood in a specific proportion are different indicators. Their determination is carried out using analysis of the lipid spectrum.
Thus, the general rate of cholesterol in blood plasma ranges from 3.6 to 5.2 mmol / l. Hypercholesterolemia is diagnosed if the amount of fatty alcohol in the blood is from 5.2 to 6.7 mmol / l (negligible), 6.7-7.8 mmol / l (medium), more than 7.8 mmol / l (heavy).
A table indicating the total acceptable cholesterol in relation to age and gender:
|Infant (from 1 to 4 years)||2.95-5.25||2.90-5.18|
|Child (5-15 years)||3.43-5.23||2.26-5.20|
|Teenage, youthful (15-20 years)||2.93-5.9||3.8-5.18|
|Adult (20-30 years old)||3.21-6.32||3.16-5.75|
|Medium (30-50 years)||3.57-7.15||3.37-6.86|
|Senior (50-70 years old)||4.9-7.10||3.94-7.85|
|Elderly (after 70-90 years)||3.73-6.2||4.48-7.25|
It is noteworthy that for people with atherosclerosis, diabetes mellitus, heart disease (ischemic syndrome) and patients who survived stroke and heart attack, the standard of cholesterol in blood serum should be less than 4.5 mmol / l.
In such diseases, a special hypolpidemic treatment is prescribed.
Types of cholesterol tests
Medicine offers many ways to determine the amount of cholesterol in the blood. One of the most popular analyzes is the Ilka method.
The research principle is based on the fact that cholestrol is treated with a special Lieberman-Burchard reagent. In the process, cholesterol loses moisture and becomes unsaturated hydrocarbon. Interacting with acetic anhydride, it is colored green, the intensity of which is detected on the FEC.
The quantitative analysis according to the Ilka method is as follows: Lieberman-Burchard reagent is poured into the tube. Then, slowly and accurately, non-hemolyzed blood (0.1 ml) is added to the container.
The test tube is shaken about 10 times and placed in a thermostat for 24 minutes. After the allotted time has passed, the green liquid is colorized on a FEC. According to the detected extinction, the value of cholesterol is determined in g / l from a standard curve.
Another popular diagnostic method for determining the amount of cholesterol is a biochemical blood test. This study also reveals carbohydrate, protein and lipid metabolism.
3-5 ml of blood from a vein is taken from a patient for analysis. Next, the biomaterial is sent to the laboratory for research.
Biochemical analysis determines the total cholestrol in the blood. On average, the indicator should not exceed 5.6 mmol / l.
Often, the cholesterol level is calculated using the Zlatiks-Zack method. The following substances are used as reagents:
- phosphate acid;
- ferric chloride;
- acetic acid;
- sulfuric acid (H2SO4).
Reagents are mixed and blood is added to them. During the oxidative reaction, it acquires one of the red shades.
Results are evaluated using a photometric scale. The number of cholesterol according to the method of Zlatiks-Zach is 3.2-6.4 mmol / l.
In some cases, screening cholesterol alone is not enough, so the patient is prescribed a lipid profile. This is a comprehensive study of the exchange of cholesterol in the body, allowing you to learn about the status of all fractions and assess the risks of atherosclerosis.
Lipidogram determines the ratio of the following indicators:
- Total cholesterol.
- High density lipoproteins. Counting is done by subtracting total cholesterol of low molecular weight fractions. The rate of HDL in men is about 1.68 mmol / l, for women - 1.42 mmol / l. In the case of dyslipidemia, the figures will be lower.
- Low density lipoproteins. The amount of harmful cholesterol is determined by analyzing the serum sediment using pyridine sulfate. Norm LDL - up to 3.9 mmol / l, if the figures are too high - this indicates the development of atherosclerosis.
- VLDL and triglycerides. Popular methods for detecting the amount of these substances are based on an enzymatic chemical reaction using glycerol, chromotropic acid, and acetylacetone. If the level of VLDL and triglycerides is more than 1.82 mmol / l, then the probability is high that the patient has cardiovascular pathologies.
- Atherogenic coefficient. The value determines the ratio of HDL and LDL in the blood. Normally, the indicator should be no more than three.
A blood test for cholesterol is described in the video in this article.