Validation of a new immunoblot assay for the diagnosis of Helicobacter pylori in the Asian population.
BACKGROUND
Performance of commercial serological tests for Helicobacter pylori varies in different populations, largely due to strain heterogeneity and variations in antigenic preparations. Currently available serology tests often show sub-optimal accuracy when used for Asian patients.


OBJECTIVE
This study evaluated a recombinant antigen-based immunoblot for the diagnosis of H. pylori infection in Chinese patients, and compared it with a conventional ELISA test.


METHODS
Dyspeptic patients referred for diagnostic endoscopy were recruited. The gold standard for H. pylori infection was based on two or more positive results among rapid urease test, histology and (13)C-urea breath test. Serological diagnosis of H. pylori infection was conducted by an ELISA test (pylori DTect; Diagnostic Technology) and an immunoblotting against a novel recombinant antigen (C1S; Genelab), which was constructed by immunological screening of the genomic DNA library of H. pylori.


RESULTS
A total of 87 patients were evaluated and H. pylori infection was diagnosed in 40 (46%) by the reference tests. The sensitivities of the ELISA and immunoblot were 80% (95% CI: 64--91%) and 90% (95% CI: 76--97%), whilst the specificities were 96% (95% CI: 86--96%) and 87% (95% CI: 74--95%), respectively. The respective likelihood ratios of the two tests were 18.6 and 7.0.


CONCLUSIONS
Satisfactory performance is obtained by the use of the new recombinant antigen-based immunoblot for diagnosing H. pylori infection in Chinese patients.
Leung
W K
WK
Department of Medicine & Therapeutics, Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong. wkleung@cuhk.edu.hk
Chow
T P
TP
Ng
E K
EK
Chan
F K
FK
Chung
S C
SC
Sung
J J
JJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000032:analysis*; D001208:Asia / Q000208:ethnology; D004269:DNA, Bacterial / Q000032:analysis; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000208:ethnology; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting / Q000592:standards*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity
D000942:Antigens, Bacterial; D004269:DNA, Bacterial