The detection of Helicobacter pylori is an important component in the assessment of patients with peptic ulcer disease. It is also recommended that physicians test for the presence of this bacteria in patients with dyspepsia. Unless endoscopy is indicated for other reasons, nonendoscopic tests for H. pylori are appropriate. Until recently, most of the tests available required a venous serum sample. A new H. pylori antibody test can use whole blood obtained from a finger-stick sample. This test is easy to perform and does not require Clinical Laboratory Improvements Amendment (CLIA) certification. Laine and colleagues study the efficacy of the fingerstick whole-blood test for H. pylori compared with endoscopic biopsy testing.
Adults who were scheduled for upper endoscopy were enrolled in the study. Patients who had recently been taking antibiotics or had been treated for H. pylori infection were excluded from the study. During endoscopy, H. pylori testing was done using the rapid urease test (CLOtest) and antral biopsies for histologic evaluation for the presence of the bacteria. After the endoscopy, patients were assessed by the fingerstick test and quantitative serologic tests for H. pylori. The gold standard for the presence of the bacteria was a positive result on the CLOtest or histologic tests. The authors also evaluated the nonendoscopic test based on the standard of the CLOtest and histologic tests being positive.
There were 201 patients enrolled in the study. The whole-blood fingerstick and enzyme-linked immunosorbent assay (ELISA) antibody tests were not significantly different in establishing the presence of H. pylori when compared with the endoscopy standards. The positive predictive value for the fingerstick test was 90 percent compared with the first endoscopy standard, while the negative predictive value was 84 percent. Using the second standard of both endoscopy tests being positive decreased the positive predictive value but increased the negative predictive value (see the accompanying table).
The authors conclude that the new-generation in-office fingerstick test for H. pylori antibody achieves results that are similar to or better than the serum ELISA tests. Therefore, the fingerstick test can be used as the initial screen for H. pylori. Newer generations of the finger-stick antibody tests now in development may provide better results than the endoscopy tests.