Pepsinogen I in serum
Reference values of the concentration of pepsinogen I in serum are 28-100 μg / l( 28-100 ng / ml).
The main cells of gastric glands synthesize and secrete pepsinogens, which are divided into 2 groups according to their immunochemical characteristics. Seven fractions of pepsinogen were identified in the blood serum, 5 of which are pepsinogen I, 2 - pepsinogen II.Pepsi-nogen I - the precursor of pepsin, is produced mainly by the main cells of the gland of the body of the stomach. A small part of pepsinogen I enters the blood, where its concentration is 6 times higher than that of pepsinogen II.Normally, pepsinogen I is found in the urine. The level of secretion of pepsinogen in the lumen of the stomach is determined by the number of major cells and is controlled by gastrin.
The content of pepsinogen I in the blood serum or the ratio of pepsinogen I / pepsinogen II with a high degree of reliability reflects the number of major cells of the glands in the area of its body, that is, the degree of atrophy of the mucous membrane of the body of the stomach. As the severity of the atrophic gastritis of the body of the stomach increases, the level of pepsinogen I and the ratio of pepsinogen I / pepsinogen II decrease. There is a positive correlation between the gastric secretion of hydrochloric acid and the level of serum pepsinogen I, on the basis of which the measurement of the latter serves as a method of indirect, or non-sonde, evaluation of gastric acidity.
In diseases associated with an increased secretory function of the stomach, an increase in the concentration of pepsinogen I in the blood serum can occur, on the contrary, when the number of major cells of the gland of the stomach decreases, it decreases. There is a linear correlation between the loss of major gastric gland cells due to atrophy of the mucous membrane and the level of pepsinogen I. The concentration of pepsinogen I in the blood serum below 25 μg / l has a 78% sensitivity and 98% specificity for the diagnosis of atrophic gastritis of the body of the stomach( medium and severe).Simultaneous detection of low concentrations of gastrin 17 and serum pepsinogen I guarantees 100% specificity in the diagnosis of atrophic gastritis. A low concentration of pepsinogen I in serum is also characteristic of pernicious anemia.
Elevated levels of serum pepsinogen I are observed in hypergastrinemia( Zollinger-Ellison syndrome, duodenal ulcer, acute gastritis).
In Fig. Algorithm for diagnosis of gastritis type was carried out using studies of AT to Helicobacter pylori, gastrin 17 and pepsinogen I in serum.