Effect of biopsies on sensitivity and specificity of ultra-rapid urease test for detection of Helicobacter pylori infection: a prospective evaluation.
OBJECTIVE
To prospectively assess the sensitivity, specificity and time to positivity of theUltra-rapid urease test (URUT) for Helicobacter pylori (H pylori), and compare the results of one with those of two biopsies.


METHODS
Five antral biopsies were taken in consecutive patients undergoing upper endoscopy: one and two biopsies for URUT, and one each for H pylori culture and histology. URUT was read at 1, 5, 10, 20 and 30 min, 1, 2, 3 and 24 h after biopsy insertion into the reagent. A positive histology and/or culture was used as positive reference "gold standards".


RESULTS
URUT was more sensitive for detecting H pylori with two biopsies rather than one, at all time points up to 120 min. The sensitivity improved from 3.6% to 82.1% for one biopsy and 10.7% to 85.7% for two biopsies from 1 to 120 min. The sensitivity reached 96.4% at 24 h for both, but the specificity reduced from 100% to 96% and 92% for one and two biopsies, respectively.


CONCLUSIONS
Development of a positive URUT result is hastened by doubling the number of gastric biopsies. We recommend taking two instead of one biopsy to achieve an earlier positive URUT result so that H pylori eradication therapy can be initiated before patient is discharged from the endoscopy suite.
Lim
Li-Lin
LL
Department of Medicine, National University Hospital, 5 Lower Kent Ridge Road, 119074 Singapore.
Ho
Khek-Yu
KY
Ho
Bow
B
Salto-Tellez
Manuel
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy / Q000379:methods*; D016099:Endoscopy, Gastrointestinal; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology / Q000473:pathology; D016481:Helicobacter Infections / Q000378:metabolism* / Q000473:pathology*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014510:Urease / Q000378:metabolism*
D014510:Urease