Alkaline Phosphatase (ALP, AKP)

Alkaline phosphatase is a phosphomonoesterase widely distributed in human tissues and body fluids, in bone, liver, breast, intestinal mucosa, kidney, and placenta. This enzyme catalyzes the removal of the 5' phosphate group from the nucleic acid molecule, thereby converting the 5'-P terminus of the DNA or RNA fragment to the 5'-OH terminus. But it is not a single enzyme, but a group of isozymes. Six isozymes of AKP1, AKP2, AKP3, AKP4, AKP5 and AKP6 have been found. The first, second, and sixth species are all from the liver, the third is from the bone cells, the fourth is from the placenta and cancer cells, and the fifth is from the intestinal villus epithelium and fibroblasts. The ALP in serum is mainly from the liver and bones. Most of the serum in children of growth phase comes from osteoblasts and growing osteochondral cells, and a small amount comes from the liver. Alkaline phosphatase assay is mainly used to diagnose hepatobiliary and skeletal diseases, and is an important indicator reflecting extrahepatic biliary obstruction, intrahepatic space-occupying lesions and rickets. Basic Information Specialist classification: Digestive examination classification: liver function test Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Common in severe chronic nephritis, celiac disease, anemia, cachexia, thyroid insufficiency or hypothyroidism in children, vitamin C deficiency scurvy. Malnutrition, stagnation, hereditary hypophosphatase. Normal value: Adult: 40-160U/L Children: 0-350U/L Above normal: Found in acute and chronic hepatitis and obstructive jaundice and other diseases. negative: Positive: Tips: Check the need for an empty stomach in the morning. Normal value Enzyme rate method (37 ° C): Adult: 40 ~ 160U / L; Children: <350U/L. (Note: The specific reference value depends on each laboratory.) Clinical significance Serum ALP measurement is mainly used for the diagnosis of hepatobiliary system and bone diseases, especially for the identification of jaundice type. (1) obstructive jaundice: patients with obstructive jaundice in the liver and outside due to poor bile excretion, ALP retention in the blood and increased, the degree of increase is proportional to the degree of obstruction, duration. Extrahepatic obstruction > intrahepatic obstruction, complete obstruction > incomplete obstruction, malignant tumor > cholelithiasis. (2) Acute and chronic hepatitis accompanied by jaundice, liver cirrhosis, liver necrosis, etc.: ALP activity is also increased. It is generally believed that ALP in patients with hepatic jaundice continues to rise at a low level, if bilirubin is gradually increased, and ALP is decreased, indicating that liver cells are severely damaged. On the contrary, it indicates that the liver cells gradually recover. ALP activity is reduced in severe diffuse liver injury. (3) Liver cancer: About half of primary liver cancer and 90% of metastatic liver cancer have elevated ALP, and the most significant increase in liver disease. Abnormally elevated ALP in patients without jaundice should be alert to the possibility of liver cancer. Other tumor ALP can also be elevated. (4) Skeletal system diseases: osteomalacia, rickets, fracture recovery period, etc., ALP activity is increased due to hyperactivity of ALP. (5) ALP activity decreased: common in cretinism, vitamin C deficiency, phosphatase hypothyroidism. Occasionally seen in hypothyroidism, pernicious anemia and malnutrition. Low results may be diseases: phosphatase deficiency in children is high. Possible diseases: chronic hepatitis precautions 1 The matrix solution should not contain free phenol. If the blank tube is red, it indicates that the phenyl phosphate disodium has been decomposed and should be reconstituted. 2 Potassium ferricyanide should be stored in the dark, and blue will be ineffective. After the addition, it should be mixed quickly to fully develop color. 3 Hemolysis and jaundice serum should be used as a self-control tube to clear the error. Inspection process Immediately after venous blood collection, the test is performed. The detection method uses p-nitrophenol phosphate as a substrate, and 2-amino-2-methyl-1-propanol or diethanolamine is a receptor for a phosphate acyl group. In an alkaline environment, ALP catalyzes the hydrolysis of 4-NPP to produce free p-nitrophenol, which is converted to yellow in an alkaline solution. The ALP activity unit was calculated based on the rate of increase in absorbance at 405 nm. Not suitable for the crowd Those without examination indications should not be tested. 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.