Diagnostic accuracy of a rapid whole-blood test for detection of Helicobacter pylori

Abstract

In this study, we evaluated a rapid whole-blood test, BM-test Helicobacter pylori, for detection of H. pylori infection in 144 and 48 patients with other gastrointestinal symptoms and with gastric cancer, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of the test correlated well with the standards used for the calculation, i.e., serology by enzyme-linked immunosorbent assay or culture and histology.As the market is flooded with new diagnostic kits for the rapid serological detection of Helicobacter pylori in the offices of general practitioners, there is an urgent need for prospective evaluation studies for different patient groups in various countries. In the present study, we included 192 Swedish endoscopy patients, both patients with gastric cancer (GC) and patients with other gastrointestinal (GI) symptoms. We compared results from culture, histology, and an ordinary enzyme-linked immunosorbent assay (ELISA) with those from a rapid wholeblood test, BM-test Helicobacter pylori (Boehringer Mannheim) for the detection of H. pylori. Culture, histology, and serology by ELISA were used to confirm existing H. pylori infection. The BM-test Helicobacter pylori was evaluated for both groups of patients, separately and together. We also correlated antibody titers, obtained by ELISA, to the visual scorings of the whole-blood diagnostic test. The aims of the present study were to evaluate the overall diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the rapid whole-blood BM-test Helicobacter pylori for patients with GI symptoms and to compare these to the results obtained for patients with GC.Patients. Forty-eight patients with GC and 144 patients with other GI symptoms were tested. The patients were included at endoscopy, and their ages ranged from 26 to 92 years for the GC group (mean age, 76 years) and from 34 to 90 years for the GI group (mean age, 74 years). Biopsies as well as serum and whole-blood samples were collected for analysis. Sera were not available from five patients (two GC and three GI group patients).Diagnosis of H. pylori infection. At endoscopy, biopsies for culture and histology were taken from the antrum and corpus areas of the stomach. Two biopsies from each location were homogenized together and cultured for isolation of bacteria according to standard procedures. Mucosal samples for histology were stained with hematoxylin and eosin stain, Alcian Blue-periodic acid-Schiff stain, and Giemsa stain. Immunohistochemical staining was performed with anti-H. pylori antibody (Dakopatts, Glostrup, Denmark). Sections were scored according to degree of inflammation and presence of H. pylori.

Extending the reading time increases the accuracy of rapid whole blood test for diagnosis of Helicobacter pylori infection

“…The performance of the BM‐Test has been evaluated with sensitivity ranging from 59.3 to 96%, and specificity from 56 to 94% 6–14 . The sensitivity of the BM‐test in the present study was 74.2% at 10 min, 91.0% at 1 h, and 94.4% at 6 h. The sensitivity at 1 h is similar to some studies read at 10 min, which have sensitivities of 91, 92 and 96%, and specificities of 56, 69, and 85%, respectively 6,8,10 . These data imply that investigators in these studies tended to treat equivocal cases as positive, and thus this increases the sensitivity but decreases the specificity.…”

“…Although it has been reported that venipuncture blood has a higher sensitivity than fingerstick blood in the FlexSure Hp ( H. pylori ) Whole Blood test, 16 no such difference was found in the Helisal Rapid Blood test 7 . The performance of the BM‐Test has been evaluated with sensitivity ranging from 59.3 to 96%, and specificity from 56 to 94% 6–14 . The sensitivity of the BM‐test in the present study was 74.2% at 10 min, 91.0% at 1 h, and 94.4% at 6 h. The sensitivity at 1 h is similar to some studies read at 10 min, which have sensitivities of 91, 92 and 96%, and specificities of 56, 69, and 85%, respectively 6,8,10 .…”

“…In contrast, there is no difference in the positive rate of urease testing between the antrum and body in the patients with duodenal ulcer 17 . We can observe that lower specificity (56–62%, 63%) was reported in studies in which only antral biopsies were evaluated, 6,12 and higher specificity (85%, 90.2%, 91%) was reported in studies in which either antrum and body specimens were evaluated or a global test such as the urea breath test was used 7,8,11 . Our higher specificity (94.1%) probably resulted from the combined effects of both antrum and body specimens being evaluated by three diagnostic modalities that would yield fewer false‐negative results, and from avoiding misinterpretation of test results by extending reading time.…”

“…Rapid whole blood testing is better than rapid serology testing as no centrifugation of the blood is needed, but the accuracy of the rapid whole blood test must be evaluated locally before its proper place in the diagnostic procedure can be determined 6 . Although the BM‐Test Helicobacter pylori has been evaluated in Western countries, 6–14 it has not been evaluated in a Chinese population. The QuikPac IV One Step Whole Blood Test is more convenient than the BM‐Test Helicobacter pylori because only one step is required, however, its sensitivity and specificity have not yet been evaluated.…”

Comparison of Two Rapid Whole-Blood Tests for Helicobacter pylori Infection in Chinese Patients

“…These tests do not require separation of serum, and results are available within minutes. Preliminary studies showed that these commercial kits may be as accurate as laboratory-based serology tests (6,10). However, data on direct comparison of different commercial kits are lacking.…”