Laboratory studies in diseases of the gastrointestinal tract
In recent years revealed a clear trend towards increased incidence of digestive system. This explains the need for continuous improvement of existing methods of diagnosis, and the creation and development of new and previously used methods to detect the disease at an early stage, to assess the degree of organ damage and monitor the results of the therapy.
Laboratory methods for the diagnosis of diseases of the gastrointestinal tract can assess changes in homeostasis. But what exactly say tests?
Laboratory studies of pancreatic diseases
Elastase-1 in stool
To assess exocrine pancreatic function “gold standard” method for determining recognized elastase-1 in feces.
Elastase-1 – organ-specific enzyme (only produced in the pancreas), is extremely stable in the intestinal contents. The volume of enzyme secretion is strongly correlated with the volume of functioning tissue cancer.
The method is used for the diagnosis of exocrine insufficiency in chronic pancreatitis, cystic fibrosis, pancreatic carcinoma, non-insulin-dependent diabetes and other diseases. The antibody used in the immunoassay determination of elastase-1 are species-specific to humans, so patients receiving enzyme preparations containing enzymes of animal origin does not affect the results and do not require interruption of treatment.
In normal pancreatic function is defined in the feces over 200 micrograms of elastase-1 to 1 g of fecal material (E / g).
At moderate insufficiency – 100-200 mg E / g
In severe deficiency – less than 100 mg E / g
Titration of enzyme replacement therapy drugs in conduct to the extent that violations of exocrine
A-amylase in the blood and urine
Amylase levels in the blood may increase for various reasons: if damaged pancreatic cells in the bloodstream enters pancreatic amylase fraction, inflammation of salivary glands – mumps – present in the blood fraction of salivary glands in the presence of bacterial contamination expressed in intestinal obstruction, peritonitis in blood enters the bacterial fraction produced by microorganisms. Therefore, the definition of high activity total amylase can not always be a sign of pancreatitis.
Laboratory methods allow us to estimate changes in the state of the organism
For the diagnosis of acute exacerbation of chronic pancreatitis and pancreatic amylase preferable to define, organ fraction (normal 8-53 IU / L).
Amylase activity increased sharply and rapidly in acute exacerbation of chronic pancreatitis and the process, but not for long – for 1-3 days. All of amylase excreted in the urine in unchanged form, so it can be determined in urine. The enzyme is stable in serum and urine at room temperature for 1 to 2 days.
The best are the specific kinetic methods (results in IU / L), outdated and less accurate method is Karaveya (results in g / l / h)
Lipase in the blood
Lipase levels in acute conditions is increased by 2 per day and is kept for at least 6-7 days. A moderate increase in chronic and possibly smoldering pancreatitis.
Violation of exocrine function, this indicator does not.
The best are the specific kinetic methods for the determination of lipase (IU / L).
Tumor marker for carcinoma of the pancreas, also can be produced by certain types of carcinoma of the colon and biliary tract. The natural way of removing this karboantigena – with bile, so in cholestasis may temporarily moderate increase in the blood. For tumors characterized by a steady increase in the concentration SA199 indicator in determining the dynamics.
Laboratory studies in diseases of the stomach and intestines
CA 242 – one of the few tumor markers, suitable for early diagnosis of tumors of the gastrointestinal tract. Increases already at stage 1 of the disease in cancer of the stomach, large intestine. Applied to the mass preventive screening and diagnosis.
CEA (carcinoembryonic antigen) – increases with carcinomas of any site with two stages of the disease, is used to diagnose at-risk groups and to monitor.
Antibodies to Helycobacter Pyl. – Detected in infected individuals as in carriers and acute process. For carriers typical levels of 10-12 IU / L, treatment to individuals with a level of more than 20 IU / l. To monitor the effect of a course of antibiotic therapy, this method is not suitable, because antibodies can circulate in the bloodstream up to 4-6 months even after successful eradication.
DNA PCR Helycobacter Pyl. – Is a direct method for diagnosis and to assess the effectiveness of eradication at 2 weeks after treatment. The material for the study – biopsy of the gastric mucosa.
Antibodies to tissue transglutaminase – a marker of celiac disease as a cause of malabsorption syndrome, chronic enterocolitis.
Fecal occult blood test – the main method for the annual mass screening for the presence of cancer of the large intestine. The use of modern immunoassay using species-specific antibodies to human hemoglobin allows wide use it to identify bleeding tumors and polyps without any restrictions for patients in the diet.
Laboratory studies in diseases of the biliary tract
Gamma-GTP – organ-specific liver enzyme – the earliest indicator of cholestasis, the first increase for any violation of the outflow of bile.
ALP (alkaline phosphatase) is present in the blood in the form of five factions – the liver, intestine, tumor, bone, and placenta. Therefore, improving the AP does not always mean it is the presence of hepatic cholestasis – the enzyme is increased in tumors, diseases of the bone and bone regeneration after injuries and operations. Children and pregnant women are normal alkaline phosphatase level is twice that in healthy adults.
CA 199 is increased in tumors of the biliary tract and pancreas.
Antibodies to Giardia – an indirect screening test for identifying infected individuals. These patients should doobsledovatsya with additional direct methods for the detection of the pathogen – Detection of Giardia in the duodenal contents, fecal Giardia cysts or three times for the presence of Giardia antigen in feces. The positive results of these studies are the basis for the diagnosis. After a course of treatment after two weeks there is a control using direct methods. Antibodies in the blood can be determined in 4-6 months even after effective therapy, so should not be used to monitor treatment.
Antibodies to pathogens opisthorchiasis – screening for evaluation of patients at risk (living in rivers Ob North Urals) who consume dried, salted fish. Direct determination – revealing opisthorchis eggs in the feces.