Diagnosing H pylori Infection

Tests to detect H. pylori infection can be divided into non-endoscopic and endoscopic tests (Table 23-1). If a patient is undergoing endoscopy, gastric biopsy, samples can be obtained for the rapid urease test (RUT) or histology; the accuracy of both these techniques is 90 to 95%. If H. pylori status is sought, the RUT is a cost effective test. If there is concern

TABLE 23-1. Tests to Detect Helicobacter pylori Infection

Sensitivity Specificity

Nonendoscopic

Blood Antibody Test1 85% 70 to 80%

Stool Antigen Test* 90 to 95% 85 to 90%

Endoscopic

Rapid Urease Test* 90 to 95% 90 to 95%

Histology* 90 to 95% 90 to 95%

Culture* 50% 100%

*Tests with decreased accuracy if patient is on proton pump inhibitors, high dose histamine-2 receptor antagonists, or antibiotics.

fMay obtain false-positive result if patient has received prior Helicobacter pylori eradication treatment.

about malignancy, gastric tissue for histology should be obtained. Most pathologists can identify H. pylori on hematoxylin and eosin stain and special stains. Accurate nonendoscopic tests include the urea breath test (UBT) and the H. pylori stool antigen test(HpSA). Both these tests are useful for initial diagnosis and also for confirmation of eradication. Because of the increasingly high rate of false-positive results, blood antibody tests are less useful, unless it is clear that the patient has not been previously exposed to H. pylori eradication therapy. Immunoglobulin G antibodies to H. pylori can remain present for years after successful eradication.

Tests that detect "active" infection include the endoscopic biopsy tests, the UBT, and the HpSA. If possible, these tests should be performed while the patient is not taking proton pump inhibitors (PPIs), high dose histamine-2 receptor antagonists, or antibiotics. These agents can decrease accuracy of the biopsy-based tests (RUT, histology), the UBT, and the HpSA by as much as 15 to 25%. Because it is not practical to stop acid-suppressing drugs before patient examination, if endoscopy is being performed, two biopsies (one from antrum and another from body of the stomach) may increase yield of the RUT in the patient on a PPI.

Constipation Prescription

Constipation Prescription

Did you ever think feeling angry and irritable could be a symptom of constipation? A horrible fullness and pressing sharp pains against the bladders can’t help but affect your mood. Sometimes you just want everyone to leave you alone and sleep to escape the pain. It is virtually impossible to be constipated and keep a sunny disposition. Follow the steps in this guide to alleviate constipation and lead a happier healthy life.

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