Campylobacter-like organism (CLO) test (rapid urease assay, Pylori-Tek, Hp-fast)

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Indications

Principle

urea + H2O -> 2 NH3 + CO2

NH3 + H2O -> NH4+ + OH-

  • the increased pH from release of NH3 results in a color change.
  • positive results may be apparent in 1 hour.
  • a final reading is obtained after 24 hours.

Sensitivity: 90-95%

Specificity: 95-100%

False negatives may occur with:

*Consider H pylori serology in patients on therapy with proton pump inhibitor or H2 blocker.

Clinical significance

Specimen

biopsy from gastric antrum

More general terms

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 328
  2. Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 342
  3. UpToDate 2004 http://www.uptodate.com