Comparison of agar gel (CLOtest) or reagent strip (PyloriTek) rapid urease tests for detection of Helicobacter pylori infection.
OBJECTIVE
Rapid urease tests (RUTs) are used commonly as a convenient method to detect Helicobacter pylori infection. New rapid tests have been commercially available with promotional literature suggesting enhanced utility. We compared CLOtest to a new reagent strip RUT, PyloriTek.


METHODS
Gastric antral mucosal biopsy specimens were obtained from 102 patients for comparison between CLOtest and PyloriTek (204 specimens). Biopsy specimens obtained from a nearby area were stained using the Genta stain for determination of H. pylori status. The RUT to be used first was selected randomly.


RESULTS
Sixty-five of the 102 patients had peptic ulcer disease, two had gastric cancer, and 35 had dyspepsia; 61 patients had active H. pylori infection. There were one false-negative and three false-positive CLOtest results, compared with one false-negative and 13 false-positive PyloriTek results (p < 0.02 for incorrect categorization with PyloriTek). Sensitivity and specificity were 98 and 92% compared with 98 and 68% for CLOtest and PyloriTek, respectively. An erroneous categorization of H. pylori status occurred in 3.9% (95% confidence interval [CI]: 1-9.7%) with CLOtest compared with 13.7% (95% CI: 7.7 -22%) with PyloriTek. When the PyloriTek was scored at 1 h (0-1 h) after obtaining the specimen, the accuracy improved; erroneous categorization of H. pylori status occurred in only 2.9% (95% CI: 0.6-8.3%).


CONCLUSIONS
Used according to manufacturer instructions, the new reagent strip RUT PyloriTek has too many false-positive results for use in a clinical situation. In contrast, when the test was interpreted within 1 h, accuracy was comparable to that of CLOtest.
Yousfi
M M
MM
Department of Medicine, Veterans Affairs Medical Center and Baylor College of Medicine, Houston, Texas 77030, USA.
El-Zimaity
H M
HM
Cole
R A
RA
Genta
R M
RM
Graham
D Y
DY
D000328:Adult; D000362:Agar; D000368:Aged; D001706:Biopsy; D004396:Coloring Agents; D016001:Confidence Intervals; D004415:Dyspepsia / Q000175:diagnosis; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology / Q000473:pathology; D005764:Gastroesophageal Reflux / Q000175:diagnosis; D016481:Helicobacter Infections / Q000175:diagnosis*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008875:Middle Aged; D010437:Peptic Ulcer / Q000175:diagnosis; D011446:Prospective Studies; D011706:Pyloric Antrum / Q000382:microbiology / Q000473:pathology; D011934:Reagent Strips; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000175:diagnosis; D014510:Urease
D004396:Coloring Agents; D011934:Reagent Strips; D000362:Agar; D014510:Urease