Examination of Lipid

Lipids are compounds that contain carbon and hydrogen is not soluble in water (hydrophobic) but soluble in organic solvents. The main lipid components that can be found in the plasma are triglycerides, cholesterol and phospholipids.
Triglycerides are fatty acids formed from the esterification of three fatty acid molecules into one molecule of glycerol. Adipose tissue triglycerides have a store that serves as a 'warehouse' fat that can be used immediately. With entry and exit of molecules in adipose tissue triglycerides, fatty acids are materials for conversion into glucose (gluconeogenesis) as well as for direct combustion to produce energy.
Fatty acids can be derived from food, but also from the excess glucose is converted by the liver and fatty tissue into energy that can be stored. More than 95% fat derived from food are triglycerides. The process of digestion of triglycerides of fatty acids in the diet (exogenous), and delivered to the bloodstream as chylomicrons (small fat droplets are covered with protein), which give the appearance of such milk or cream in serum after consumption of foods high in fat content.
Cholesterol comes from food and endogenous synthesis in the body. Source of cholesterol in foods such as egg yolks, milk, meat, fat (lard), and especially in a state sebaginya ester. In the intestine, the ester is then hydrolyzed by cholesterol esterase originating from the pancreas and formed free cholesterol absorbed by the intestinal mucosa with chylomicrons as a means of transport to the lymphatic system and eventually into the venous circulation. Approximately 70% esterified cholesterol (combined with a fatty acid), and 30% in free form.
Cholesterol is synthesized in the liver and intestine and is found in erythrocytes, the cell membrane, and muscle.
Most of the cholesterol the body needs is synthesized from acetyl coenzyme A through betahidroksi betametil glutamyl-CoA. Cholesterol is important in cell wall structure and the materials that make the skin waterproof. Body uses cholesterol to form bile salts as a facilitator for the digestion of fat and for the formation of steroid hormones (eg cortisol, estrogen, androgen) by the adrenal gland, ovary, and testis.
Phospholipid, lecithin, sphingomyelin, and sefalin is a major component in the cell membrane and also worked in the solution to change the surface tension of liquid (eg liquid surfactant activity in the lung). Phospholipids in the blood from the liver and intestine, as well as small amounts of synthesis in various tissues. Phospholipids in the blood may participate in cell metabolism and also in blood coagulation.
Because lipids are not soluble in water, then it requires a 'carrier' in order to enter the blood circulation. The carrier is a protein called lipoproteins. Lipoproteins in the circulation consists of particles of various sizes that also contain cholesterol, triglycerides, phospholipids, proteins in different amounts so that each density lipoproteins have different characteristics. Lipoprotein s largest and lowest density is chylomicrons, followed by very low density lipoprotein (very low density lipoprotein, VLDL), low density lipoprotein (low density lipoprotein, LDL), lipoprotein density medium (intermediate density lipoprotein, IDL), and high density lipoprotein (high density lipoprotein, HDL).
Most of the triglycerides in plasma are not in the fasting state in the form of chylomicrons, whereas the fasting plasma samples, triglycerides mainly contained in the form of VLDL. Most of plasma cholesterol contained in LDL. Fraction (15-25%) in HDL cholesterol.
Exogenous pathway or the transport of fatty foods involves the absorption of triglycerides and cholesterol through the intestines, accompanied by the formation and release of chylomicrons into the lymph flow of blood through the dank e duktur torasikus. Chylomicrons deliver triglycerides to the adipose tissue while circulating in the circulation. In addition, also activates lipoprotein lipase to release free fatty acids from triglycerides thus reduced to the size of the chylomicron remnant eventually absorbed by the liver. Fatty acids are released in turn absorbed by muscle and adipose cells.
VLDL is mainly formed by liver cells, in part by the intestine. Mainly consist of VLDL triglycerides are formed by endogenous liver cells from carbohydrates. He served to bring out the cholesterol from the liver to the tissues to be stored as energy reserves.
LDL derived from VLDL catabolism, carries cholesterol in the blood plasma to peripheral tissues for the exchange of substances. Containing 45% LDL cholesterol. LDL is easy to stick to the walls of coronary arteries, causing the crust cholesterol (plaque). That's why LDL is often referred to as "bad cholesterol".
HDL is formed by the liver and intestinal cells, in charge of siphoning deposits of cholesterol in tissues, and transported to the liver and then throw it into the bile. Therefore, the HDL-called "good cholesterol". When a low HDL, the cholesterol will be deposited on the arterial network.
Measurement of Lipid
Determination of serum lipids is usually done, but can also use EDTA plasma or heparin plasma. Both serum and plasma should be immediately separated from blood cells and if not immediately checked, must be stored in the refrigerator so that the distribution of cholesterol did not change and the enzymes could not change the proportion of lipoprotein. Blood samples should be obtained after the client fasted 10-12 hours before the shooting.
Measurement of serum lipids that are most relevant is the total cholesterol, triglycerides, HDL cholesterol, and LDL cholesterol. Lipid measurements can be performed by chemical colorimetric method.
Total cholesterol measurements can use the enzyme cholesterol oxidase. Triglycerides were measured through the hydrolysis of fatty acids expenditure followed by quantification of the liberated glycerol. HDL cholesterol measurements using the precipitation of all lipoproteins other than HDL, and HDL cholesterol remaining in solution was measured. Whereas LDL cholesterol was measured from the measurement of triglycerides, total cholesterol, and HDL cholesterol by the Friedewald approach as follows:
LDL cholesterol = total cholesterol - HDL cholesterol - (triglycerides / 5)
This calculation is valid for triglyceride levels up to about 400 mg / dL.
Now the measurement of LDL cholesterol can be done directly by the technique of selective imunopresipitasi other lipoprotein fractions.
Reference values
Triglycerides
ADULT: Age 12-29 years: 10-140 mg / dl. Age 30-39 years: 20-150 mg / dl. Age 40-49 years: 30-160 mg / dl. Age> 50 years: 40-190 mg / dl.
Children: Infants: 5-40 mg / dl. Age 5-11 years: 10-135 mg / dl.
Total cholesterol
ADULT. Ideal value: <style = "font-style: italic;"> The risk is: 200 - 240 mg / dl. High risk:> 240 mg / dl. Pregnancy: high risk levels, but will be back to normal like before pregnancy 1 month after birth.
CHILDREN. Infants: 90-130 mg / dl. Children aged 2-19 years: the ideal of 130-170 mg / dl, the risk is 171-184 mg / dl, high risk> 185 mg / dl.
HDL cholesterol
Age 20-24 years: 30-79 mg / dl. Age 25-29 years: 31-83 mg / dl. Age 30-34 years: 28-77 mg / dl. Age 35-39 years: 36-62 mg / dl. Age 40-44 years: 34-67 mg / dl. Age 45-49 years: 30-87 mg / dl. Age 50-54 years: 28-92 mg / dl.
LDL cholesterol
Recommended: Medium risk: 130-159 mg / dl. High risk:> = 160 mg / dl.
Meanwhile, according to PERKENI (Society of Endocrinology Indonesia) in 2004, serum lipid levels that are considered optimal and abnormal can be seen in the following table:
Total cholesterol (mg / dl)

200 or less

The desired
200-239

Height limit
240 or more

Height
LDL cholesterol (mg / dl)

100 or less

Optimal
100-129

Close to optimal
160-189

Height
190 or more

Very High
HDL cholesterol (mg / dl)

40 or less

Low (less good)
60 or more

High (good)
Triglycerides (mg / dl)

150 or less

Normal
150-199

Height limit
200-499

Height limit
500 or more

Very high
Clinical Problem
Elevated levels of blood fats can cause coronary artery disease or risk of cardiovascular disease. Elevated levels of cholesterol (hypercholesterolemia) causing accumulation of fat in the crust of the coronary arteries (arteriosclerosis) and the risk of heart disease (myocardial infarction). High serum cholesterol levels may be associated with genetic predisposition (hereditary), biliary obstruction, and / or dietary intake. Increase in triglycerides in a long time will be blubber under the skin and cause obesity. Excess blubber would also be altered LDL cholesterol. High LDL cholesterol and low HDL cholesterol is a risk of atherosclerotic disease. Conversely, a low LDL cholesterol and high HDL cholesterol may reduce the risk of coronary artery disease.
Increased cholesterol levels can be found at: infak infarction (MCI) acute, atherosclerosis, hypercholesterolemia, family, hiperlipoproteinemia type II, III and V, high-cholesterol diet (animal fats). It is also found in: hypothyroidism, biliary obstruction, biliary cirrhosis, myxoedema, infectious hepatitis, uncontrolled diabetes mellitus, nephrotic syndrome, pankreatektomi, III trimester of pregnancy, periods of severe stress. The influence of drugs: aspirin, kostikosteroid, steroids (anabolic and androgenic agents), oral contraceptives, epinephrine and norepinephrine, bromide, phenothiazines (chlorpromazine [Thorazine], trifluoperazin [Stelazine]), Vitamin A and D, sulfonamides, phenytoin (Dilantin)
Increased levels of triglycerides can be found at: hiperlipoproteinemia, acute myocardial infarction, hypertension, cerebral thrombosis, arteriosclerosis, high-carbohydrate diet. Also can be found at: hypothyroidism, nephrotic syndrome, cirrhosis of Laennec or alcoholism, uncontrolled diabetes mellitus, pancreatitis, Down syndrome, stress, pregnancy. The influence of drugs: Estrogens, oral contraceptives.
Increase in blood fats are generally influenced by dietary factors. Consumption of foods high in calories for a long time, especially a lot of fat, causing a persistent increase in triglycerides are mainly located in VLDL particles. High carbohydrate intake leads to increased triglyceride and VLDL fast. Cholesterol in the diet increases LDL cholesterol content, as well as saturated fatty acid intake through food, the consumption of unsaturated fatty acids may reduce total cholesterol. Alcohol increases the concentration of triglycerides, VLDL and primarily affects the occasional chylomicrons.
Factors that can affect laboratory findings:

    Aspirin and cortisone medications can cause a decrease or an increase in serum cholesterol levels,
    High-cholesterol diet is consumed prior to the examination led to an increase in serum cholesterol levels,
    Severe hypoxia may increase serum cholesterol levels,
    Hemolysis on blood samples can lead to increased serum cholesterol test results,
    Diets high in carbohydrates and alcohol can increase serum triglyceride levels.