Welcome to the SIBO Testing Center, located in Portland, OR. We specialize in SIBO testing and we are associated with a well-known Naturopathic Clinic, Portland Natural Medicine (PNM), Inc. We offer the 3 hour Lactulose Breath test, which is the breath test of choice for diagnosing elevated hydrogen and/or methane gases that are associated with Small Intestinal Bacterial Overgrowth.