Mucosal polymerase chain reaction for diagnosing Helicobacter pylori infection in patients with bleeding peptic ulcers.
OBJECTIVE
Helicobacter pylori (H pylori) has been linked to chronic gastritis, peptic ulcers, gastric cancer and MALT-lymphoma. Conventional invasive tests are less sensitive than non-invasive tests in diagnosing H pylori infection in patients with bleeding peptic ulcers. Polymerase chain reaction is a sensitive and accurate method for diagnosing H pylori infection. The aim of this study was to evaluate the diagnostic role of mucosal polymerase chain reaction for H pylori infection in patients with bleeding peptic ulcers.


METHODS
In patients with bleeding, non-bleeding peptic ulcers and chronic gastritis, we checked rapid urease test, histology, bacterial culture and mucosal polymerase chain reaction for detecting H pylori infection. Positive H pylori infection was defined as positive culture or both a positive histology and a positive rapid urease test. For mucosal polymerase chain reaction of H pylori, we checked vacA (s1a, s1b, s1c, s2, m1, m1T, m2), iceA1, iceA2 and cag A.


RESULTS
Between October 2000 and April 2002, 88 patients with bleeding peptic ulcers (males/females: 60/28, gastric ulcers/duodenal ulcers: 55/33), 81 patients with non-bleeding peptic ulcers (males/females: 54/27, gastric ulcers/duodenal ulcers: 45/36) and 37 patients with chronic gastritis (males/females: 24/13) were enrolled in this study. In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, 45 patients (51%), 71 patients (88%) and 20 patients (54%) respectively were found to have positive H pylori infection (P<0.001). In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, polymerase chain reaction for H pylori infection was positive in 54 patients (61%), 70 patients (86%) and 20 patients (54%) respectively (P<0.001). The sensitivity, positive predictive value and diagnostic accuracy of mucosal polymerase reaction for H pylori infection were significantly lower in patients with bleeding peptic ulcers (84%, 79% and 81%) than in patients with non-bleeding peptic ulcers (99%, 99% and 98%) (P<0.001, P<0.01 and P<0.001 respectively). The sensitivity, negative predictive value and diagnostic accuracy of mucosal polymerase reaction for H pylori were significantly lower in patients with bleeding peptic ulcers (84%, 83% and 81%) than in patients with chronic gastritis (100%, 100% and 100%) (P = 0.02, P = 0.02 and P = 0.001).


CONCLUSIONS
Mucosal polymerase chain reaction for detecting H pylori infection is not reliable in patients with bleeding peptic ulcers.
Lin
Hwai-Jeng
HJ
Division of Gastroenterology, Department of Medicine, VGH-Taipei, Taiwan, China. hjlin@vghtpe.gov.tw
Lo
Wen-Ching
WC
Perng
Chin-Lin
CL
Tseng
Guan-Ying
GY
Li
Anna-Fen-Yau
AF
Ou
Yueh-Hsing
YH
D000368:Aged; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D005756:Gastritis / Q000382:microbiology; D016481:Helicobacter Infections / Q000175:diagnosis*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D010437:Peptic Ulcer / Q000382:microbiology; D010438:Peptic Ulcer Hemorrhage / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000592:standards*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity