Apolipoprotein CI

Apolipoprotein C is the major apolipoprotein of very low density lipoprotein cholesterol. It is also present in high density lipoprotein-cholesterol and low density lipoprotein-cholesterol. There are 3 different apolipoproteins C, namely ApoCI, ApoCII, ApoCIII, which is a small amount of structural protein of CM, VLDL and HDL. Basic Information Specialist classification: cardiovascular examination classification: biochemical examination Applicable gender: whether men and women apply fasting: fasting Tips: Actively cooperate with the doctor during the examination. Normal value The enzyme immunoassay is 37 to 99 mg/L. Clinical significance The effects of activated lipoprotein esterase and lecithin cholesterol ester acyltransferase are important for elucidating the function of lipoprotein C, lipoprotein metabolism, and the causes of hyperlipidemia and cardiovascular disease. Precautions Before the examination, pay attention to rest and ban diet. Inspection process (1) Immunoturbidimetry: 1 Regarding antiserum: The turbidimetric assay has higher requirements for antiserum than other methods. The turbidimetric method is preferably a polyclonal antibody. Anti-serum must be free of anti-serum. Must pay great attention to the apoA-I extracted from human serum to achieve immunopurity, chromatographic purity and electrophoresis purity, which is not possible in the general laboratory. The antiserum titer (titer) should not be less than 16. At present, in some domestic commercial reagents, the apoA-I antiserum has a very low titer, so care must be taken when purchasing the kit. If you do not have experience in identifying antisera quality before purchase, you should ask the qualified unit to identify it. 2 The upper standard specimen (serum) is diluted 200 times for manual operation (100 μl of sample), and if there is a precision sampler, it can be diluted 20 times (using 10 μl). In order to adapt to the conditions of different laboratories (such as different types of automated instruments), the proportion of antigen-antibody should be paid attention to when making appropriate modifications. It must be noted that there should be no antigen excess in the reaction system, and the linear upper limit should not be lower than 2.5g/L. In other words, the amount of antiserum must be sufficient, otherwise the results are low when the apoA-I is high in the specimen. At present, some domestic drug kits not only have low anti-serum titer, but the dosage of the specimens in the operation is too large (such as 3 ~ 5μl), the antibody is obviously insufficient, and the measured results are inevitably inaccurate. 3 In order to achieve accurate measurement, the calibration curve calculation results must be made in the apoA-I and B turbidimetric assays (endpoint method). A certain range (low sample dosage) concentration (X) is basically linear with turbidity (Y), and linear regression calculates a certain intercept on the Y-axis (A value <0.1), so the deviation of the calculation result is calculated by single point calibration. Larger, the measured results can not accurately reflect the level of high (high low, low high). Do not neglect the accuracy of the measurement because of the simplicity of the single point method. Regardless of the type of automated instrument, you must first try the calibration curve. If the test is repeated under the conditions of the instrument and the specific conditions, the intercept of the regression line is not obvious, then the single point calibration method can be used. When the amount of the sample is 3 to 5 μl, even if the amount of antiserum is increased, the concentration and the turbidity are not linear, and can only be calculated after the curve is linearly converted. 4 The main interference factor is the turbidity of the serum itself (such as high-fat serum), and the pretreatment methods such as ultracentrifugation or lipase hydrolysis are not practical. The effect of turbidity with surfactants is also limited, so a blank tube must be made in the assay. In addition to the two-point method used in automated analysis, it is a mistake to manually use a single reagent without subtracting the specimen blank. In order to reduce the effect of matrix effects on the turbidity response, fixed-value serum must be used as a calibrator. In addition, interference such as dust particles and turbid dish scratches must be excluded. 5 Some commercial kits (including some imported products) with inaccurate calibration sera values ​​are an important source of error. (2) Rocket electrophoresis method: 1 The dilution ratio of the antigen and the amount of antiserum should be selected so that the rocket peak is clear, the slope of the calibration curve is moderate, and the line is suitable. The method simultaneously measures apoA-I and apoB, and the amount of the two antisera should be adjusted so that the peak heights of the two are different, and the apoB peak height is not less than 1 cm. 2 Different kinds of antiserums (such as rabbits and sheep) are tested at the equivalent price, and the results will be different. The apoA-I assay is preferably rabbit antiserum. When the rabbit serum is used, the peak shape is sharp, and the peak produced by the sheep serum is thick, the peak tip is round and blunt, and sometimes a ghost image appears before the peak. The slope of the calibration curve for the calibration serum is also different. However, no matter what antiserum is used, the quantitative results are not much different. 3 Electrophoresis under certain conditions, the peak height of the calibration serum of different dilutions will not change significantly, and the slope of the calibration curve is basically the same. If the peak height of the specimen exceeds the calibration curve range, the specimen dilution factor should be adjusted and retested. The inter-board CV is typically less than 5%. 4 Rocket electrophoresis results can be observed by staining or direct visual observation of the rocket peak. The former uses less specimens and saves antiserum, but if the specimens and antiserum are appropriately increased, it is more convenient to not stain. The agarose used should be standard electroosmotic or hypotonic. Adding proper amount of dextran or polyethylene glycol to the gel will make the rocket peak clearer. 5 The measurement of the rocket peak can calculate the area or peak height, and the area is the peak height multiplied by the peak width (the width at the half height of the peak). The measurement accuracy is preferably up to 0.1 mm. Mechanical or electronic amplification equipment must be used. The peak height in the range of the standard curve is preferably 1 to 4 cm. 6 This method is applicable to the analysis of a small amount of specimens. Also suitable for apoAII, CI, CII, CIII, D, E and Lp (a) determination. Not suitable for the crowd Generally no crowds. Adverse reactions and risks 1. Infection: Pay attention to aseptic operation when collecting blood, avoid contamination of water and other parts at the blood collection site to avoid local infection. 2, bleeding: after the blood is given a full compression time, especially coagulopathy, bleeding tendency, to avoid local subcutaneous oozing, bruising and swelling.