Lipase (LPS) is mainly derived from the pancreas and is a group of enzymes that are not specific. This enzyme acts only on the interface between oil and water, and the reaction rate is related to the particle size in the substrate emulsion. The smaller the particles, the larger the contact surface area and the faster the reaction rate, and the lower the concentration of the substrate in the emulsion. Therefore, the preparation of a uniform and long-term preservation of the substrate emulsion is an important and difficult problem in the process, and olive oil emulsions are now often used to formulate the substrate. The measurement methods are roughly titration and turbidimetry.Basic Information
Specialist classification: Digestive examination classification: biochemical examination
Applicable gender: whether men and women apply fasting: fastingTips: The use of heparin, calcium, bile salts, phosphatidylcholine, etc. can make LPS results higher; oral contraceptives are the opposite. Normal value
1. The enzymatic reaction by titration is from 0.06 to 0.89 U/ml for 4 h and from 0.2 to 1.5 U/ml for 16 to 24 hours.
2. The turbidimetric method is positively skewed, with the lowest being OU and the one-sided 95% upper limit being 7.9U.Clinical significance
1, elevated in acute and chronic pancreatitis, pancreatic stasis (pancreatic cancer, pancreatic cyst, cholangiocarcinoma, cholelithiasis, papillary cancer, etc.), renal insufficiency, pancreatic injury, perforated peritonitis, pancreatic duct obstruction (calculus, opium, can Waiting, methylcholine). The pancreas is the main source of human LPS. Increased serum LPS is common in acute pancreatitis and pancreatic cancer, occasionally in chronic pancreatitis. In acute pancreatitis, serum amylase increases for a shorter period of time, and serum LPS activity increases for 10 to 15 days. When mumps does not affect the pancreas, LPS is usually in the normal range. In addition, total bile duct stones or cancer, intestinal obstruction, duodenal perforation, etc. may also increase.
2, reduced in the late stage of pancreatitis, pancreatic resection and so on.High results may be diseases: aphid acute pancreatitis, acute pancreatitis in the elderly, pediatric acute pancreatitis, secondary peritonitis, pregnancy with acute pancreatitis, biliary acute pancreatitis, post-traumatic brain fat embolism
1. There are no special requirements before blood draw.
2, the use of heparin, calcium, bile salts, phosphatidylcholine, etc. can make LPS results higher, oral contraceptives are the opposite.Inspection process
1. Titration method: According to Table 1.
The blank tube and the measuring tube were titrated with 0.05 mol/L sodium hydroxide until a long-lasting light gray-blue color was obtained, and the number of milliliters of sodium hydroxide used for titration was recorded.
2, turbidimetric method:
1 Add 4ml olive oil emulsion to the test tube, pre-warm at 37 °C for 5min, add 0.05ml serum, immediately mix and invert 5 times (do not shake vigorously!), quickly use the spectrophotometer to be turbid, adjust the zero point with Tris buffer, The absorbance was read at a wavelength of 400 nm as A1.
2 The tube was placed in a 37 ° C water bath for 10 min, and then the absorbance was read as A2.
3 If the enzyme activity is very high, the substrate will be completely cleared during the incubation period, and the serum to be tested should be appropriately diluted with Tris buffer and then re-operated.
4 standard curve preparation, take 4 test tubes, respectively, add olive oil emulsion 1.0, 2.0, 3.0 and 4.0ml, then add to the 4.0ml with Tris buffer, the equivalent of triglyceride concentrations are 0.17, 0.34, 0.51 and 0.68μmol , the same as the turbidity, draw a standard curve.Not suitable for the crowd
Inappropriate people: Generally there are no people who are not suitable.Adverse reactions and risks
1, local subcutaneous hemorrhage: after the blood collection should be pressed for a sufficient time, especially those with bleeding tendency, so as not to cause subcutaneous oozing and bruising due to no blood coagulation.
2, infection: attention to aseptic operation during venous blood collection, so as not to cause local infection.