H. Pylori Stool Antigen Test Research Articles

More economic 25 mg 13C‐urea breath test can be effective in detecting primary Helicobacter pylori infection in children

The high cost of the 13C-urea breath test (UBT) limits its wide application for both epidemiological and clinical studies for diagnosing Helicobacter pylori infection. This study examined if a lower-dose UBT, applying 1 mg/kg of bodyweight (maximum 25 mg, UBT(25)), could introduce cost savings while preserving high diagnostic yields for primary H. pylori infection. Children aged less than 16 years were recruited after obtaining consent. Those children with administration of antibiotics or proton pump inhibitors within 1 month of the tests were excluded. Positive tests for both the UBT with 50 mg urea (UBT(50)) and the H. pylori stool antigen (HpSA) were qualifying criteria for H. pylori infection. Negative results for both indicated non-infection. The UBT(25) was conducted 1 week after the UBT(50). The cut-off points for the UBT(25) ranging from 2delta to 5delta were examined for their sensitivity, specificity and accuracy rates. A total of 153 children were recruited (55% male; mean age 9.1 +/- 3.5 years). Both the UBT(50) and HpSA test were positive in 18 (13.1%) and negative in 119 children, respectively. The sensitivity and specificity of the UBT(25) were optimally achieved at 88.9% (95% confidence interval [CI]: 71.4-100) and 95.0% (95% CI: 91.1-99.9), judged with a cut-off point at 3.5delta. The diagnostic accuracy was significantly higher for children older than 7 years than for those younger than 7 years (98%vs 85%, P = 0.009). Lower-dose UBT titration by bodyweight can cut costs while maintaining a highly reliable method to screen primary H. pylori infection in children older than 7 years, which is generally beyond school age.

Quantitative Correlation of Helicobacter pylori Stool Antigen (HpSA) Test with the Severity of H. pylori-Related Gastritis

The Helicobacter pylori (H. pylori) load in both stomach and stool and the resulting severity of gastritis are important criteria in validating the status of H. pylori infection. We aimed to assess the reliability of the H. pylori stool antigen (HpSA) test for the primary diagnosis of H. pylori infection by calculating the best cut-off value to obtain the highest sensitivity and specificity in dyspeptic patients. We also investigated the correlation of HpSA test with the severity of gastritis and H. pylori load. The H. pylori statuses of 95 patients were evaluated by the positivity of both rapid urease test and microscopic detection of H. pylori in biopsy specimens, 88 subjects of whom were H. pylori positive. The sensitivity and specificity of the HpSA test were 51.1% (45/88) and 100% (7/7), respectively, according to the manufacturer's recommended cut-off value of 0.16. However, with the best cut-off value of 0.048, calculated by receiver operator characteristics analysis, the sensitivity of the test increased to 92.0% (81/88) with the same specificity. High values of the HpSA test were correlated with high scores of corpus H. pylori load and the severity of antrum and corpus inflammation (p < 0.05). With the best cut-off value of the HpSA test, the primary diagnosis of H. pylori infection can be made with higher sensitivity and specificity. The HpSA test is a helpful tool that evaluates the severity of H. pylori infection and the degree of gastric inflammatory activity and gastric H. pylori load.

Accuracy ofHelicobacter pyloristool antigen for the detection ofHelicobacter pyloriinfection in dyspeptic patients

The premier platinum Helicobacter pylori (H pylori) stool antigen (HpSA) test is an enzyme immunoassay (EIA) that detects an H pylori antigen present in human stools. However, at present there is no uniformity about the cut off level required to consider the test as positive or negative. So we need the cut off level for our local population. The aim of this study was to evaluate the HpSA for the detection of H pylori infection in dyspeptic patients and to determine the sensitivity, specificity of the HpSA test in the diagnosis of H pylori infection, as compared to other standardized diagnostic techniques. Sixty-three dyspeptic patients were selected from patients who came to the Division of Gastrointestinal Clinic in Cipto Mangunkusumo Hospital, Jakarta, Indonesia. H pylori infection was confirmed in all patients by histology and rapid urease test (CLO test). Positive results for H pylori were based on positive results from both rapid urea test and microscopic detection of H pylori. Stool specimens were analyzed for H pylori antigen using HpSA immunoassay. A total 63 patients consisted of 31 (49.2%) males and 32 (50.8%) females ranging in ages between 16 and 73 years with a mean age of 42.4+/-15 years. The mean age of men was 43.2+/-15.7 years and women was 41.6+/-14.4 years. Endoscopic findings in this study included gastric cancer 1.6%, peptic ulcer 4.8%, duodenal ulcer 7.9%, esophagitis 6.3%, gastritis 77.7%, and gastroduodenitis 4.8%. According to the predefined study criteria, 6 (9.5%) of 63 patients were positive for H pylori. In the diagnosis of infection, the area under the receiver operating characteristic (ROC) curve for the HpSA test was 0.722 (95% CI, 0.518-0.927). Using a cut-off value of 0.274 instead of 0.16 (as recommended by the manufacturer) the sensitivity and the specificity were 66.7% and 78.9% respectively. The HpSA stool test, using a cut-off value of 0.274, may be useful for the primary diagnosis of H pylori infection, its specificity is similar to other standard tests but its sensitivity was lower.

Diagnosis of Helicobacter pylori infection by stool antigen test in southern Taiwan.

Helicobacter pylori (H. pylori) has been found to be associated with various gastrointestinal diseases. Confirmation of H. pylori infection includes invasive and non-invasive methods. There has been increasing interest in noninvasive tests recently. However, the geographical differences among H. pylori strains have been emphasized recently and the H. pylori strain in Taiwan showed a high cagA positive result and different vacA subtype when compared with those of Western countries. The aim of this study is to access and compare the reliability and the diagnostic accuracy of the stool H. pylori antigen tests by spectrophotometry and by the visual method, especially in Southern Taiwan. Thirty-two patients (18 men and 14 women; age range: 23-91 y/o, mean: 50.5 y/o) who underwent gastroendoscopy at Kaohsiung Medical University Hospital were enrolled in this study. H. pylori infection status was confirmed by culture or two positive test results on CLO test, histology and 13C-urea breath test (13C-UBT). The exclusion criteria included previous gastrointestinal tract surgery, use of antibiotics, proton pump inhibitor or compounds containing bismuth within 1 month of the study. Among them, 14 patients were with duodenal ulcer (DU), 4 with gastric ulcer (GU), 12 with non-ulcer dyspepsia, and 2 with GU and DU. Those patients had their stool collected for ELISA tests of H. pylori stool antigen (HpSA). The HpSA tests were positive in 16 of 18 patients diagnosed as H. pylori positive, and negative in 13 of 14 patients as H. pylori negative. The sensitivity and specificity were 88.9% and 92.9% respectively. The positive and negative predictive values were 94.1% and 86.7% respectively. The concordance of HpSA accessed by spectrophotometry and visual method is 100%, which makes this test even easier and cheaper. We concluded that stool HpSA test is a noninvasive, accurate, reliable, rapid and easy way to diagnose H. pylori infection in Southern Taiwan, either by spectrophotometry or by visual assessment.

Eficacia de la determinación fecal de Helicobacter pylori mediante la técnica HpSA en enfermos con hemorragia digestiva alta

The rapid urease test is the most commonly used test in the diagnosis of Helicobacter pylori infection in patients with upper gastrointestinal hemorrhage. However, some studies have suggested that results of this test are frequently false negative when blood is present. An effective new enzyme immunoassay for determining H. pylori antigens in stools has recently begun to be used. To determine the efficacy of the H. pylori stool antigen test (HpSAT) in patients with upper gastrointestinal hemorrhage. Thirty-two patients with upper gastrointestinal hemorrhage were prospectively studied from November 1998 to April 1999. In all patients the following tests were performed in the first 72 hours after onset of bleeding and 24 hours after hospital admission: upper gastrointestinal endoscopy, biopsy samples for the rapid urease test and histological study, blood samples for serology, stool samples for HpSAT, and the 13C urea breath test. Criteria for infection was a positive result in at least two of the four diagnostic techniques, except in the case of HpSAT. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. Of the 32 patients, 23 (71.8%) were infected. The results of four HpSAT (12.5%) were negative and 28 were positive (87.5%). HpSAT showed high sensitivity (95.6%) but low specificity (33.3%). The PPV and NPV were 78.5% and 75% respectively. Of the 32 HpSAT, 25 (78.1) were performed in melenic stools: 22 were positive and 3 were negative. Seventy-five percent of negative HpSAT and 78.5% of positive HpSAT corresponded to melenic stools. HpSAT is a rapid, non-invasive technique that does not appear to be influenced by the presence of blood. Consequently, it can be applied in patients with upper gastrointestinal hemorrhage. The rapid urease test showed high sensitivity, specificity and PPV and should remain the first-line test in patients with upper gastrointestinal hemorrhage. HpSAT is appropriate as a second-line technique and is useful when the rapid urease test is negative and infection is strongly suspected, when no samples for the rapid urease test have been taken and when endoscopy cannot be performed. The result obtained in the present study should be confirmed in future studies with larger samples.