Health Questions and Answers

Question: What endoscopy-based (invasive) tests can be used to diagnose Helicobacter pylori infection?

Answer:

Histopathologic examination is widely available, and specimens are easy to store. Organisms can be detected with standard hematoxylin and eosin stains or special stains, such as Giemsa or Warthin-Starry, which make the organisms easier to identify. The sensitivity and specificity of histopathology for H. pylori are greater than 95% but may be influenced by sampling error, number of organisms present, use of proton pump inhibitors, and experience of the pathologist.
Rapid urease testing relies on the potent urease activity of H. pylori, when a gastric biopsy specimen is placed in medium containing urea and a colored pH indicator. If the organism is present in the specimen, its urease hydrolyzes urea to bicarbonate and ammonia, increasing the pH and changing the color of the pH indicator. The number of organisms present, use of certain medications, and sampling error may influence urease testing. The sensitivity of the rapid urease test is approximately 90%; its specificity is 100%.

Reference:
Vaira D, Gatta L, Ricci C, Miglioli M: Review article: Diagnosis of Helicobacter pylori infection. Aliment Pharmacol Ther 16(Suppl 1):16-23, 2002.

Leave a Reply