title: Efficiency of the glutaraldehyde test strip for monitoring the concentration of glutaraldehyde in reused solutions for disinfecting endoscopes.
abstract: BACKGROUND
  Glutaraldehyde has been widely used for low-temperature disinfection of endoscopes. The current practice at Siriraj Hospital is to change the glutaraldehyde solution every 21 days or when the solution appears turbid. The disadvantages of this practice include inadequate disinfection of endoscopes if the concentration of glutaraldehyde in a reused solution is insufficient or wasted if the discarded solution is still active.
  
  
  OBJECTIVE
  To determine the efficiency of a glutaraldehyde test strip (GTS) in monitoring the amount of glutaraldehyde in a reused solution for disinfecting endoscopes.
  
  
  METHODS
  Reused glutaraldehyde solutions for disinfecting bronchoscopes, gastroscopes and colonoscopes were tested for the concentration of glutaraldehyde with a GTS thrice weekly for the first week and then every working day up to 56 days. If the GTS indicated a concentration of glutaraldehyde > or = 1.8 per cent after 21 days, 5 ml of the solution was taken to the laboratory to determine its mycobactericidal activity.
  
  
  RESULTS
  All samples of the reused glutaraldehyde solution up to 56 days with a concentration of > or = 1.8 per cent glutaraldehyde on GTS from testings showed mycobactericidal activity. If the glutaraldehyde solution was reused for up to 28, 42 or 56 days, it could save 9,603; 22,813 and 29,415 baht per year respectively for the gastroscopy and colonoscopy units. The corresponding figures were -949; 2,726 and 4,564 baht per year for the bronchoscopy unit. It is estimated that up to 400,000 baht per year could be saved by adopting the strategy of GTS monitoring in all endoscopy units at Siriraj Hospital.
  
  
  CONCLUSIONS
  The current strategy of discarding reused glutaraldehyde solution in the gastroscopy, colonoscopy and bronchoscopy units at Siriraj Hospital may be inappropriate since the reused solution is still mycobactericidal for up to 56 days.
authors.affiliation: Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
authors.forename: Anuwat
authors.initials: A
authors.lastname: Keerasuntonpong
authors.forename: Pratya
authors.initials: P
authors.lastname: Sitaposa
authors.forename: Angkana
authors.initials: A
authors.lastname: Chaiprasert
authors.forename: Visanu
authors.initials: V
authors.lastname: Thamlikitkul
mesh_terms: D020680:Bronchoscopes / Q000382:microbiology; D020685:Colonoscopes / Q000382:microbiology; D004203:Disinfection / Q000379:methods*; D019723:Endoscopes / Q000382:microbiology*; D004866:Equipment Contamination / Q000517:prevention & control*; D017743:Equipment Reuse; D005069:Evaluation Studies as Topic; D020699:Gastroscopes / Q000382:microbiology; D005976:Glutaral / Q000494:pharmacology*; D006801:Humans; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D012996:Solutions; D013785:Thailand
chemical_list: D011933:Reagent Kits, Diagnostic; D012996:Solutions; D005976:Glutaral