Laboratory parameters of the 2nd order – depending on the results of the history, physical examination, etc. – for differential diagnostic clarification
- Antibody levels to parietal cells and intrinsic factor – for suspected autoimmune gastritis (type A gastritis) [detection of parietal cell AK (PCA; 30-60% of cases), intrinsic factor antibodies].
- Serum pepsinogens – in suspected autoimmune gastritis (type A gastritis) [low pepsinogen I or decreased pepsinogen I/II ratio → advanced atrophy of acid-producing gastric glands indicating (sensitivity (percentage of diseased patients in whom the disease is detected by the use of the test, i.e. i.e. a positive test result occurs) 96%, specificity (probability that actually healthy people who do not suffer from the disease in question are also detected as healthy by the test) 95%); endoscopic/histological (fine-tissue) clarification of the stomach required!]
- If necessary, a determination of the vitamin B12 serum level can also be made.
- Helicobacter pylori detection by:
- 13C-urea breath test
- Histology (gold standard)
- Culture, serology: AK against Helicobacter pylori and CagA antigen (cytotoxin associated gene A antigen – virulence factor).
- For therapy control: C13 breath test with detection of labeled CO2 from H. pylori metabolism; in children as a non-invasive diagnostic or also for therapy control of the adult: Helicobacter pylori antigen detection in stool (6 to 8 weeks after the end of therapy).