Two novel enzyme immunoassays (EIAs) that assess the presence of Helicobacter pylori infection in stool samples — the H. PYLORI QUIK CHEKÔ and the H. PYLORI CHECKÔ — were found to be highly efficacious without significant cross-reactivity, according to the findings from a study published in the European Journal of Clinical Microbiology and Infectious Diseases.
Patients (N=271) were prospectively recruited from the United States, Europe, and Bangladesh between 2017 and 2018. Participants underwent esophagogastroduodenoscopy for symptoms of dyspepsia, peptic ulcer, or gastritis during which at least 6 gastric biopsy specimens were obtained. The specimens were assessed by histologic tests and for urease. Patients provided a stool sample when they had not been exposed to antibiotics or bismuth compounds for at least 2 weeks.
The stool samples were tested by the H. PYLORI QUIK CHEKÔ (rapid membrane EIA) and H. PYLORI CHECKÔ (microwell EIA) as instructed by TechLab Inc. A positive H pylori test was one with an optical density of ³0.120 (450 nm) at single wavelength or ³0.080 (450/620) nm at dual wavelength. Samples were also tested with 2 established H pylori assays: the ImmunoCard STAT! HpSA (rapid test) and the Premier Platinum HpSA Plus (microwell test).
Participants had a mean age of 46.2 (standard deviation [SD], 15.2) years, 68.2% were women, 29.9% were taking proton pump inhibitors, and 23.2% were positive for H pylori infection on the basis of histologic testing and urease analysis (composite method).
The 2 EIAs were indeterminate for 10 individuals.
Among the remaining 261 participants, the H. PYLORI CHECKÔ and H. PYLORI QUIK CHEKÔ had higher sensitivities (92% and 91%) and specificities (91% and 100%) compared with the composite method, and the tests had high negative predictive values (NPVs; 97% and 97%) and positive predictive values (PPVs; 76% and 98%), respectively.
Compared with the 2 commercially available assays, the 2 EIAs performed similarly to the ImmunoCard STAT! (sensitivity, 92%; specificity; 97%; PPV, 91%; NPV, 97%) and outperformed the Premier Platinum Plus (sensitivity, 87%; specificity; 87%; PPV, 68%; NPV, 96%).
Among participants who had not used proton pump inhibitors, the efficacy of the H. PYLORI CHECKÔ (sensitivity, 93%; specificity; 99%; PPV, 98%; NPV, 97%) and H. PYLORI QUIK CHEKÔ (sensitivity, 95%; specificity; 90%; PPV, 82%; NPV, 97%) assays increased.
The 2 EIAs were challenged with common intestinal bacteria (n=38) and viruses (n=6). All positive tests remained positive and all negative tests remained negative, indicating no cross-reactivity.
This study was limited by the imbalance of gender among participants and for geographic-related differences in positive results across test sites.
The study authors concluded that these rapid EIAs, which gave results the same day, were highly efficacious for detecting H pylori infection with no evidence of cross-reactivity with common bacteria or viruses.
Disclosure: An author is an employee at TechLab, the manufacturer of the H. PYLORI QUIK CHEKÔ and the H. PYLORI CHECKÔ, and TechLab provided a research grant for patient recruitment and sample collection. Please refer to the original article for a full list of disclosures.
Halland M, Haque R, Langhorst J, Boone JH, Petri WA. Clinical performance of the H. PYLORI QUIK CHEK™ and H. PYLORI CHEK™ assays, novel stool antigen tests for diagnosis of Helicobacter pylori. Eur J Clin Microbiol Infect Dis. Published January 3, 2021. doi:10.1007/s10096-020-04137-7