Clo Test

From Anvita Health Wiki

Contents 1 Indications 2 Principle 3 Clinical-significance 4 Specimen 5 More General Terms 6 References

Indications

• H pylori

Principle

• one or 2 pieces of tissue are placed in an agar well containing urea & a pH indicator
• urease derived from H pylori (or Campylobacter-like organism) cleaves urea & releases NH3 & CO2
  

• 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:

• recent gastrointestinal bleeding
• use of proton pump inhibitor* of H2 antagonists*
• antibiotics or bismuth-containing compounds
  *Consider H pylori serology in patients on therapy with proton pump inhibitor or H2 blocker.

Clinical-significance

• test for urease activity of Campylobacter-like organism (CLO)

Specimen

• biopsy from gastric antrum

More General Terms

• clinical microbiology test

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 [1]

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