Digestive Testing: Let's Figure Out What's Going On

If your gut isn’t happy, chances are you’re not so happy either. Digestive concerns can be incredibly inconvenient and troublesome. They’re some of the most common complaints I help patients resolve. If you’re frustrated with smelly gas, infrequent or unpredictable poops (constipation, diarrhea, or a combination of the two), abdominal pains, or your belly bloats up to look like you’re pregnant, it’s time to seek some help. A naturopathic doctor can be a great place to start. We (NDs) recognize the foundational importance of digestion to your overall health, and are thoroughly trained in assessment and treatment options (ranging from nutrition and herbal medicines, all the way to prescription medications).

Whether you see your medical doctor or naturopathic doctor, it’s important to ask them if any tests are indicated. Your symptoms and medical history provide great clues as to what is going on, alongside a hands-on physical exam, but lab tests can often show a more detailed picture, one very specific to your body. The results of these tests will also allow your clinician to make your treatment plan as individualized as possible. 

We can separate digestive testing into three main categories, based on what kind of sample we’re testing: blood, breath, or stool. Each category provides a window into different compartments of the body. Any one person typically only needs one or a few select tests, chosen based on your symptoms and history. All must be ordered and interpreted by a doctor. There are many tests available, but I’ll highlight some of the most common. 

Tests marked with a * are ND-specific tests. The others can be ordered by either an ND or an MD. Sometimes, ND-specific tests provide direction and clarity when conventional testing hasn’t produced information to guide further treatment. So, please, if you’re struggling despite being told your labs are all “normal”, keep seeking answers. 

Blood Tests

• Digestive Organs and Infection Screening Tests 

  • Several basic blood tests provide information about digestive function, including: enzyme production, liver and gallbladder function, and nutrient absorption (eg. iron and B12 levels). 

  • Markers of infection or inflammation can also provide valuable clues. 

• Celiac Test (Anti-TTG) 

  • Celiac disease is an autoimmune condition in which patients are intolerant of gluten. Diagnosis requires a positive biopsy of the small intestine (showing intestinal damage), but the first step in testing for celiac is the anti-TTG blood test. Patients must be eating gluten for several weeks prior to the test, or a false negative can occur. 

  • Another test, which measures IgA antibody levels, is usually run at the same time to ensure the person is producing enough total IgA antibodies for the TTG (one type of IgA antibody) test to be accurate.

• IgG Food Sensitivity Test*

  • Food sensitivities are immune responses to specific foods that promote issues within the body (bloating, constipation or diarrhea, headaches, acne, or eczema). A food sensitivity is not a food allergy. They present differently and are mediated by different types of immune cells. Read more about the differences here. Several studies have demonstrated positive effects of removing foods found to be reactive on an IgG food sensitivity test, especially for: IBS, migraine headaches, and weight loss.

  • Testing is simple and quick. A small blood sample is collected via finger poke and sent away to the lab. The results are sent back within a couple weeks, showing which foods were reactive, and to which degree. This provides guidance of which foods to eliminate for a time in what’s called an “elimination diet” (the gold standard for identifying food sensitivities). 

Breath Tests 

• H pylori Urea Breath Test

  • H pylori is a common bacteria that colonizes in the gastrointestinal tract, and can be involved in cases of upper abdominal discomfort, nausea, and ulcers. 

  • If you or your doctor suspect a current H pylori infection, you’ll need the breath or stool test, not the blood test. A blood test will show a positive result for past as well as current infections, so breath (or stool) is usually best.

  • There are some special preparations for this test, so be sure to read the instruction sheet before you head to the lab. 

• Lactose Tolerance Hydrogen Breath Test 

  • Many people suspect they are lactose intolerant (cannot digest milk or milk products). Did you know you can confirm it with a test? The test is done at the lab and measures hydrogen levels produced after ingesting a high-lactose drink. Hydrogen levels will be high in your breath if you aren’t digesting lactose well. 

  • In BC, this test must be paid privately. 

• SIBO Breath Test*

  • SIBO (Small Intestine Bacterial Overgrowth) is a condition in which bacteria are present in the wrong amounts, or wrong types in the small intestine, leading to bloating and gas, constipation or diarrhea (depending on the bacteria present), nausea or acid reflux. It’s estimated that many people diagnosed with IBS also have SIBO. 

  • The SIBO breath test is done in the comfort of your home. Several breath samples are given after drinking a lactulose solution. These samples provide information about which gases your microbiome (resident bacteria) are producing at different points in your digestive tract. Proper interpretation of the test allows accurate SIBO diagnosis and guides targeted and individualized treatment specific to the prominent type of bacteria present if you are positive for SIBO. You can learn more about SIBO here.

Stool Tests

• Basic Culture + Ova and Parasites 

  • These tests are ordered if a gastrointestinal infection is suspected (such as persistent travellers diarrhea). Stool samples can be analyzed for growth of many common infectious organisms - bacterial or parasitic. If pathogens are detected, guidance on the most appropriate treatment agents is also provided. 

  • The sample is collected at home and brought to the lab for testing. 

• Comprehensive Stool Culture*

  • This panel assesses both type and quantity of bacteria, yeast, and parasites. Not only does it detect the presence of infectious organisms but it  will also show any imbalance in the number of good bacteria. The test assesses digestive function and nutrient absorption, as well as markers of intestinal inflammation, seen in inflammatory bowel disease (IBD - Crohn’s or Colitis). It can be useful for many different digestive concerns. If pathogens are detected, guidance on the most appropriate treatment agents (herbal or prescription antibiotic or antifungals) is also provided. 

  • The sample is collected at home and mailed to the lab for testing. 

• FIT (Fecal Immunoculture Test) 

  • This test detects microscopic blood in your stool and is part of routine screening for colon cancer. In BC, anyone between the ages of 50-74 is eligible for screening every two years (even without symptoms), but it can be ordered outside those ages or more frequently if symptoms are present. The sample is collected at home and brought to the lab for screening. 

As you can see, there are MANY tests available! Choosing the right test is equally as important as interpreting the results alongside your symptoms. If you’re struggling to find digestive relief, have a discussion with your doctor (medical or naturopathic) who can help you choose which tests (if any) are indicated for you.