Negative CLOtest pellet can be reused

• Published in: Gastrointestinal endoscopy 1999-08, Vol.50 (2), p.225-228
• Main Authors: Lee, Chia-Long, Tu, Tien-Chien, Dai, Yuan-Chang, Wu, Chi-Hwa, Chen, Tzen-Kwan, Ma, Van-Long, Lin, Horng-June, Hu, Ruey-Tyng
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biopsy; Culture Techniques; Digestive system; Equipment Reuse; Esophagitis, Peptic - diagnosis; Esophagitis, Peptic - pathology; Gastric Mucosa - microbiology; Gastric Mucosa - pathology; Gastritis - diagnosis; Gastritis - pathology; Helicobacter Infections - diagnosis; Helicobacter Infections - pathology; Helicobacter pylori - enzymology; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Peptic Ulcer - diagnosis; Peptic Ulcer - pathology; Predictive Value of Tests; Stomach Neoplasms - diagnosis; Stomach Neoplasms - pathology; Urease - analysis
• ISSN: 0016-5107; 1097-6779
• DOI: 10.1016/S0016-5107(99)70229-4

Background: The CLOtest is based on the production of ammonia from urea in the presence of urease. In theory, substrate that has not been consumed in a negative test can be reused. Methods: We collected negative CLOtest pellets after their first use and stored them at room temperature. Whenever a CLOtest was needed during endoscopy, two biopsy specimens were taken from the antrum. One specimen was tested with a new CLOtest and the other with one that had been used previously. Time to color change was observed in paired tests. Results: We used 216 previously used CLOtest pellets with biopsy specimens obtained from 317 patients. Of the paired tests, 204 matched positive and 108 tested negative. Only 5 paired tests had discrepant results. Three had positive results only with a new CLOtest, and 2 were positive only with the reused test. In positive paired tests, there was significant linear correlation in log-transformed color change time between reused and new tests (p < 0.001). Ninety-two percent of previously used pellets were reused fewer than three times before they yielded a positive color change; the interval to this occurrence ranged from 2 to 15 days. Compared with the new CLOtest, the sensitivity of the reused CLOtest was 98.6% and the specificity was 98.2%. Conclusions: A negative CLOtest kept at room temperature can be reused within a short period of time, in circumstances in which there are environmental and economic considerations to be taken into account. (Gastrointest Endosc 1999;50:225-8.)