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H. pylori Urease

Helicobacter pylori Urea

Test Codes

EPIC: LAB5515

Department

Microbiology

Instructions

• The Urease Test Slide should be stored refrigerated (2-8°C or 36-46°F) and warmed to room temperature before use. Slide gel should be clear yellow or light peach. If it is green or blue, it should not be used.
  
• Patients should not have taken antibiotics or bismuth salts for at least three weeks prior to endoscopy. Suppression of H. pylori by these agents makes the organism difficult to detect by any means, and re-growth of H. pylori may be patchy, leading to false negative results in the first few weeks after treatment.

Specimen Collection Criteria

Collect: Gastric mucosal biopsy specimen. Insert the specimen deep into the HP Fast Urea Gel Slide.

Transport STAT to the Laboratory. Time of collection must be documented on the labeled test device.

Rejection Criteria

Specimens not collected and processed as indicated.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Specimens are disposed once testing is completed. 

Laboratory

Royal Oak Microbiology Laboratory

Performed

Monday – Friday, 7:00 am – 3:30 pm.
Results available within 24 hours.

Reference Range

Negative.

Test Methodology

Enzyme-Mediated Color Change.

Interpretation

Helicobacter pylori is detectable in nearly 100% of adult patients with duodenal ulcer and about 80% of patients with gastric ulcer. An association with gastric cancer has been confirmed.

False negative results may occur when very low numbers of H. pylori are present, or the bacterium has a patchy distribution. For example, in 1-5% of patients, the bacterium is present in the body of the stomach but not in the antrum, or vice versa. As H. pylori do not colonize intestinal mucosa, a false negative urease test can result. There may be a case therefore for performing two urease tests, one from the antrum and one from the body mucosa.

All tests for H. pylori will be less sensitive if the patient has recently taken antibiotics or bismuth. Re-growth of H. pylori may be patchy after suppression with antibiotics.

False positive Urease tests are rare. They may occur if old, slightly orange tests are used. A false positive could occur in patients who have achlorhydria. False positive results can also occur in patients with pernicious anemia, previous gastric surgery, and/or those who have recently taken antacids, or large doses of H₂ receptor antagonists. In the absence of acid, urease-producing commensal organisms such as Proteus spp. can grow in the stomach. However, these organisms produce less urease than H. pylori and it will take more than 3 hours to produce a color reaction in the test system.

Specimens containing blood may result in a false positive result.

Since therapy for H. pylori is only 50-75% effective at present, physicians may elect to re-assess the patient 28 days after completing therapy to confirm eradication. Biopsies taken before this time may produce false negative results due to patchy re-growth of the organism.

Reference

1. American Academy of Pediatrics. Helicobacter pylori Infections. In: Peter G, ed. (1997) Red Book: Report of the Committee on Infectious Diseases. 24rd ed. Elk Grove Village, IL: American Academy of Pediatrics; 1997:231-232.
2. HP Fast Package Insert. HPIFU,07. Diagmed Healthcare, Ltd.
3. Bartlett, M.S. 2011. Induced Sputum: Stained Preparations for Detection of Pneumocystis carinii, Garcia, L.S., Editor-in-Chief. Clin. Microbiol. Proc. Handbook, 3^rd Edition, ASM Press, Washington, D.C., 8.3.2.

CPT Codes

87077

Contacts

Last Updated

4/4/2024