serum cholesterol

There are two sources of cholesterol in the human body, namely, in vivo synthesis and absorption from food, mainly in vivo synthesis. The liver is the main organ that synthesizes, stores, and supplies cholesterol in the body. Cholesterol is divided into two parts in serum, namely cholesterol ester (ChE) and free cholesterol (Ch) bound to fatty acids, of which about 2/3 of total cholesterol is bound to fatty acids. Cholesterol is a kind of lipid compound with many important physiological functions. It is a synthetic adrenal cortex hormone, sex hormone, vitamin D3, bile acid and an important component of cell membrane. It plays an important role in human growth and metabolism. However, the concentration of cholesterol in the blood is too high, which can cause intravascular deposition to damage the heart and brain blood vessels, and form atherosclerosis, causing cardiovascular and cerebrovascular diseases. The liver is the main regulating organ involved in cholesterol synthesis and decomposition, so the cholesterol measurement also reflects the function of liver lipid metabolism. Basic Information Specialist classification: Digestive examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Primary hypocholesterolemia, familial no-beta lipoproteinemia, familial hypo-beta lipoproteinemia, and the like. Normal value: Umbilical cord: 1.17-2.60mmol/L Newborn: 1.37-3.50mmol/L Infant: 1.82-4.55mmol/L Children: 3.12-5.20mmol/L Youth: 3.12 - 5.46mmol / L Adult: 2.9-6.00mmol/L Above normal: Primary hypercholesterolemia, familial hypercholesterolemia, familial mixed hypercholesterolemia, and the like. negative: Positive: Tips: Before the examination, the diet is light, alcohol is forbidden, and the morning is needed for an empty stomach. Normal value Enzymatic method (37 ° C): Umbilical cord: 1.17 ~ 2.60mmol / L (45 ~ 100mg / dl); Newborn: 1.37 ~ 3.50mmol / L (52 ~ 135mg / dl); Infant: 1.82～4.55mmol/L (70～175mg/dl); Children: 3.12 ~ 5.20mmol / L (120 ~ 200mg / dl); Youth: 3.12 ~ 5.46mmol / L (120 ~ 210mg / dl); Adult: 2.9 to 6.00 mmol/L (110 to 230 mg/dl). Clinical significance 1. Elevation: primary hypercholesterolemia, familial hypercholesterolemia, familial mixed hypercholesterolemia, multifactorial hypercholesterolemia, β-sitosterolemia, familial high α- Lipoproteinemia, familial type III hyperlipidemia, familial V-type hyperlipidemia, familial type I hyperlipidemia (LPL deficiency), secondary hypercholesterolemia, hypothyroidism, Diabetes, Cushing's syndrome, acromegaly, obesity, long-term use of steroid preparations, oral contraceptives, stress response, nephrotic syndrome, systemic lupus erythematosus, diabetic glomerulosclerosis, obstructive jaundice, gallbladder Calculus, common bile duct tumor, primary biliary cirrhosis, liver cancer, multiple myeloma, glycogen accumulation disease (VonGierKe), regression-type febrile non-suppurative nodular panniculitis (WeberChristian disease), fat metabolism Disorders, excessive intake of saturated fatty acids and cholesterol, pregnancy, etc. 2, reduction: primary hypocholesterolemia, familial no-beta lipoproteinemia, familial hypo-lipoproteinemia, Tangier disease (familial high-density lipoprotein deficiency syndrome), secondary hypocholesterolemia Symptoms, hyperthyroidism, severe liver damage (cirrhosis, acute hepatitis, severe hepatitis, acute fatty liver in primary pregnancy, toxic hepatitis), Banti syndrome, digestive malabsorption syndrome, cachexia, anemia With malnutrition (hunger, advanced cancer, uremia, steatorrhea). High results may be diseases: hyperlipidemia, familial hypercholesterolemia, diabetes considerations 1. When applying the automatic analyzer, the reaction procedure can be designed according to the instrument conditions and reagent reaction conditions. Automated analyzers require fast enzyme reactions (preferably within 5 minutes). Reactive reagents can only be used for manual manipulation and colorimetrically until the reaction reaches the end. Reagents and specimens can be scaled up or down according to the cuvette volume. 2, in order to ensure that the enzyme reaction is rapid, completely and beneficial to the long-term stable preservation of the enzyme reagent, the enzyme preparation is required to have good performance and excess enzyme. After the enzyme reagent is formulated, it should be stored at 4 ° C for more than 3 days. Different batches of reagents should be checked for reaction arrival time, color stability and linear range. 3. If the cholesterol content in the sample exceeds the linear range of the reagent (the range of the general enzyme reagent should be within 5g/L), the specimen can be diluted with physiological saline and the result must be multiplied by the dilution factor. 4, serum bilirubin below 0.1g / L, ascorbic acid below 0.05g / L and mild hemolysis does not affect the results. The amount of other steroids in the serum is very small and does not cause significant interference. 5. When the instrument is stable and the operator is skilled, the CV within the batch is <1%, and the CV between the batches is <2%. 6, because pure cholesterol and serum cholesterol matrix, the reaction rate is different, the use of pure cholesterol standard results in the enzymatic determination is often low. Therefore, it is recommended to use the standard reference serum as the standard to achieve the same reaction as the serum sample, and the standard reference serum application reference method is based on the standard cholesterol adhering to the international standard. The standard serum can be stored at -20 ° C for 1 year. It is not advisable to freeze and freeze repeatedly. Inspection process 1. Pipette serum samples, standards, and water (blank) each 20 μl. 2. Add 2 ml of enzyme reagent and mix for several seconds with a vortex mixer. 3, 37 ° C water bath insulation for 10 ~ 15min. 4, colorimetric. Zero the reagent blank. The absorbance values ​​of the standard and serum samples were read separately. Note: 1. When applying the automatic analyzer, the reaction procedure can be designed according to the instrument conditions and reagent reaction conditions. Automated analyzers require fast enzyme reactions (preferably within 5 minutes). Reactive reagents can only be used for manual manipulation and colorimetrically until the reaction reaches the end. Reagents and specimens can be scaled up or down according to the cuvette volume. 2, in order to ensure that the enzyme reaction is rapid, completely and beneficial to the long-term stable preservation of the enzyme reagent, the enzyme preparation is required to have good performance and excess enzyme. After the enzyme reagent is formulated, it should be stored at 4 ° C for more than 3 days. Different batches of reagents should be checked for reaction arrival time, color stability and linear range. 3. If the cholesterol content in the sample exceeds the linear range of the reagent (the range of the general enzyme reagent should be within 5g/L), the specimen can be diluted with physiological saline and the result must be multiplied by the dilution factor. 4, serum bilirubin below 0.1g / L, ascorbic acid below 0.05g / L and mild hemolysis does not affect the results. The amount of other steroids in the serum is very small and does not cause significant interference. 5. When the instrument is stable and the operator is skilled, the CV within the batch is <1%, and the CV between the batches is <2%. 3. Because pure cholesterol is different from serum cholesterol matrix, the reaction rate is different. If the pure cholesterol standard is used in the enzymatic determination, the result is often low. Therefore, it is recommended to use the standard reference serum as the standard to achieve the same reaction as the serum sample, and the standard reference serum application reference method is based on the standard cholesterol adhering to the international standard. The standard serum can be stored at -20 ° C for 1 year. It is not advisable to freeze and freeze repeatedly. Not suitable for the crowd Leukemia, various anemia, myelodysplastic syndrome and other patients, unless the examination is essential, try to draw less blood. Adverse reactions and risks 1, subcutaneous hemorrhage: due to pressing time less than 5 minutes or blood draw technology is not enough, etc. can cause subcutaneous bleeding. 2, discomfort: the puncture site may appear pain, swelling, tenderness, subcutaneous ecchymosis visible to the naked eye.