Elastase-1 (pancreatic elastase-1) is a special enzyme produced by the pancreas. A study for the presence of this enzyme is carried out using biochemical analysis. This indicator has an independent diagnostic value, but it is most often studied together with the determination of amylase level, UAC and coprogram. The identification of the level of this indicator in feces is used in order to assess the functioning of the pancreas. This analysis is performed by ELISA, using feces for it, which is collected in a sterile container. The normal rate for an adult ranges from 201 mcg / g. Examination of samples can last from one to nine days.
What is elastase?
Elastase is an enzyme that is part of the hydrolase group. Its molecular weight reaches 28,000 carbon units. When compared with other proteases, this enzyme is able to break down the structural protein that makes up the elastic fibers of connective tissue, the walls of blood vessels, and skin. Elastase is of two forms - pancreatic and leukocyte.
Where is synthesized?
Pancreatic elastase-1 is synthesized in the pancreas, and then secreted as proelastase into the small intestine along with other enzymes. In the small intestine, under the action of a serine protease, it is transformed into elastase. PE-1 in the intestine does not break down, which is why its concentration in the stool is an indicator of the regulation of the amount and composition of pancreatic juice secreted by the pancreas.
Which group does it belong to?
Together with chymotrypsin and trypsin, elastase belongs to the group of serine proteases. This is due to the fact that the active center contains serine. All enzymes previously listed make up about 40% of the total concentration of proteins of the exocrine region in the pancreas. All of them are one family. PE-1 has a higher specificity than trypsin. Therefore, its activation occurs during the separation of peptide bonds formed by amino acids. Also, elastase is able to take part in the process of cleavage of the elastin protein, which does not decompose under the influence of trypsin and chymotrypsin.
Determination of pancreatic elastase in feces is often used to diagnose cystic fibrosis. As a result of the disease, cystic fibrosis, which is a genetic pathology, there is a violation in the structure and functionality of the cells that are on the excretory ducts of the glands. Cystic fibrosis provokes damage to the lungs, stomach, kidneys, intestines. In this case, an analysis for pancreatic elastase will detect a significant decrease in fecal mass. The test for this indicator is a highly sensitive and specific research method, which is widely used in gastroenterology, hepatology and endocrinology.
Indications for analysis
An analysis to determine the level of pancreatic elastase-1 can be assigned to determine the insufficiency of the secretory activity of the pancreas, in the diagnosis of cystic fibrosis, malignant neoplasms, pancreatitis in a chronic form. In addition, the study was shown to monitor the treatment of pancreatic enzyme deficiency .
A study for pancreatic elastase (the norm will be presented below) can be prescribed if the following symptoms are observed:
- Diarrhea or constipation.
- Bloating.
- Pain and heaviness in the abdomen after eating.
- A sharp decrease in body weight.
- Change in the consistency, color and smell of feces.
- The presence in the feces of residues of incompletely digested food.
There are no contraindications to this analysis.
The specificity of the study of feces on the content of elastase-1 in it can reach 95%, and the sensitivity is almost 93%. Another advantage of this study is the low ability of pancreatic elastase-1 to cleave. This allows you to save material for a long time, if you comply with all the conditions of its collection.
Preparation for research and collection of material for its conduct
For research, you need to take a sample of feces. It is preferable to take an analysis in the morning, in the interval from 7 to 11 in the morning. Before the study, food is allowed. This is due to the fact that the elastase that comes with food in the intestine does not break down and cannot affect the result of the study. It is important not to take laxatives, not to use rectal suppositories and barium preparations for several days before the test. It is necessary to pass the analysis before other manipulations such as an enema or colonoscopy are performed.
The treatment and the result of the study on the content of elastase-1 in the stool also have no effect on drug treatment, which involves taking pancreatic enzymes.
When collecting biomaterial, several rules should be observed. It is necessary to observe the sterility of the container and make sure that urine does not enter the stool sample. Then you should transfer the sample of feces to a special container in the amount of 30-60 milliliters and close tightly with a lid. Until the feces are sent for research, it should be stored in the refrigerator. The temperature should be between five and eight degrees. You can collect feces for this study during the day, and if necessary, it can be frozen at a temperature of -20 degrees.
Research method
When conducting the analysis, the enzyme immunoassay is used. The lab technician applies a layer of antibodies that can recognize only elastase-1 on a plastic tablet for ELISA. Then, a sample of the studied biomaterial is attached to the antibodies. A dye tag is applied to the biotin site. The intensity of marker staining is determined by spectrophotometry.
Normal enzyme values in biomaterial
Elastase-1 in a newborn baby is slightly lower than normal, but by the age of two weeks they reach a normal level. Analyze the data should only a highly qualified specialist. The interpretation of the results is as follows.
- EP values> 200 μg / g indicate normal pancreatic function. The higher the value, the better the function of this organ (when pancreatic elastase> 500 mcg / g or just 500 is good).
- The value of 100-200 μg / g is mild pancreatic insufficiency.
- The value of EP <100 μg / g - moderate or severe organ failure.
That is, if the indicator is more than normal, it will have no clinical significance. But when the study revealed an insufficient level of elastase, it is necessary to begin treatment.