1st order laboratory parameters – obligatory laboratory tests.
- Invasive methods:
- Culture [sensitivity 70-90%, specificity 100%]
- Histology (gold standard) after endoscopic biopsy (tissue sample) [sensitivity 80-98 %, specificity 90-98 %]
- Urease rapid test (synonym: Helicobacter urease test; trade name: CLO test) – biopsy is thereby given into a urea-containing color indicator solution (bedside test) [sensitivity 90-95 %, specificity 90-95 %]Note: inhibition of enzyme activity (false negative test result) by proton pump inhibitors (proton pump inhibitors, PPI) and antibiotics; false-positive findings due to a bacterial (not H. pylori) overgrowth in the stomach Patient preparation: No therapeutic agents before biopsy (tissue sampling) (PPI 1 week, antibiotics 6 weeks).
- Pathogen detection by PCR (polymerase chain reaction) [sensitivity 90-95%, specificity 90-95%].
- Non-invasive methods:
- 13C-urea breath test – indirectly measures the activity of the bacterial enzyme urease [sensitivity 85-95%, specificity 85-95%].
- Stool antigen test using monoclonal antibodies [sensitivity 85-95%, specificity 85-95%]
- IgG antibodies in serum [sensitivity 70-90%, specificity 70-90%]
Therapy control: 13C-urea 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 end of therapy).
Indications:
- According to the German guideline, two positive test results are required for a reliable diagnosis.
- One positive test result is considered sufficient with simultaneous detection of:
- Duodenal ulcer
- Chronic active gastritis
- A positive culture (specificity 100%)
- The following minimum time intervals without Helicobacter pylori suppressive therapy must be observed for a reliable diagnosis:
- Two weeks after the end of proton pump inhibitor (PPI) therapy.
- Four weeks after previous H. pylori eradication or antibiotic therapy.
- Tests not recommended for clinical diagnosis:
