Novel monoclonal antibody-based Helicobacter pylori stool antigen test.
BACKGROUND
A number of noninvasive tests have been developed to establish the presence of Helicobacter pylori infection. Although polyclonal antibody-based stool antigen testing has a good sensitivity and specificity, it is less accurate than urea breath testing. Recently, a monoclonal antibody-based stool antigen test demonstrated an excellent performance in diagnosing H. pylori infection in adults and in pediatric populations.


OBJECTIVE
To evaluate the diagnostic accuracy of a novel stool test based on monoclonal antibodies to detect H. pylori antigens in frozen human stool in the pretreatment setting.


METHODS
Stool specimens were prospectively collected from 78 patients undergoing gastroscopy and stored at -20 degrees C until tested. Helicobacter pylori infection was evaluated by histology, rapid urease testing and urea breath tests ((13)C-UBT). Positivity of the three tests was considered the gold standard for H. pylori active infection. Patients with no positive test were considered negative. The gold standard was compare to the results of the monoclonal antibody stool antigen test. Frozen stool specimens were tested using a novel monoclonal-antibody-based enzyme immunoassay (HePy-Stool, Biolife-Italiana, Milan, Italy).


RESULTS
The sensitivity and specificity of the monoclonal stool antigen test were 97%[95% confidence interval, (CI) 86-100] and 94% (95% CI: 81-99), respectively. Negative and positive predictive values were 97% (95% CI: 85-99), and 95% (95% CI: 83-99), respectively. The diagnostic accuracy was 96% (95% CI: 88-99). The likelihood ratio for a positive test was 17 and for a negative test was 0.


CONCLUSIONS
Although the (13)C-UBT is the most accurate among the available noninvasive tests, our results show that an H. pylori stool test using monoclonal antibody might be an excellent alternative.
Dore
Maria Pina
MP
Institute of Internal Medicine, Spedali Civili, Brescia, Italy. mpdore@ssmain.uniss.it
Negrini
Riccardo
R
Tadeu
Vincenza
V
Marras
Lea
L
Maragkoudakis
Emanouel
E
Nieddu
Salvatore
S
Simula
Luigi
L
Cherchi
Giovanni Battista
GB
Massarelli
Giovanni
G
Realdi
Giuseppe
G
D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000942:Antigens, Bacterial / Q000032:analysis*; D005243:Feces / Q000382:microbiology*; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000382:microbiology; D016480:Helicobacter pylori / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D011933:Reagent Kits, Diagnostic