Is saliva serology useful for the diagnosis of Helicobacter pylori?
BACKGROUND
The Cortecs Diagnostics Helisal Assay test is a quantitative immunoassay for salivary IgG antibodies against Helicobacter pylori. Saliva can be obtained simply with the kit in the general practitioners surgery.


OBJECTIVE
To compare the new saliva serological test for H pylori with 'gold standard' evidence of H pylori infection (antral biopsy specimens for histology, culture, and urease test) and a new serum serological test.


METHODS
Eighty six unselected dyspeptic patients undergoing endoscopy.


METHODS
Each patient provided saliva and serum before endoscopy for H pylori serology, which was compared against 'gold standard' evidence of infection.


RESULTS
Thirty two patients were H pylori positive by the 'gold standard' tests. At a cut off value of 0.15 EU/ml the saliva test had a sensitivity of 88% and a specificity of 71%, with a negative predictive value of 90%. If patients who were taking omeprazole or had recent antibiotics are excluded, the sensitivity is unchanged but the specificity increases to 79%. The serum test had a similar sensitivity of 85% but better specificity of 78%.


CONCLUSIONS
Serum testing remains the best serological test for H pylori in the hospital setting. Saliva testing may have a role in epidemiological studies and in screening dyspeptic patients in general practice, especially in children in whom venesection is more difficult.
Christie
J M
JM
Gloucester Gastroenterology Group, Gloucestershire Royal Hospital.
McNulty
C A
CA
Shepherd
N A
NA
Valori
R M
RM
D000907:Antibodies, Bacterial / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D016481:Helicobacter Infections / Q000175:diagnosis*; D016480:Helicobacter pylori / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D012463:Saliva / Q000276:immunology* / Q000382:microbiology; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G