If you’re considering functional testing, you’ve probably come across names like GI360, DUTCH, Organic Acids (OAT) and SIBO. These advanced tests can provide insights that routine bloodwork often misses, but how do you know which one is right for you?
This guide breaks down what each test does, who it’s most useful for and how they fit together.
GI360 Stool Test
- Best for: Persistent bloating, IBS, IBD, diarrhoea/constipation, food sensitivities, post-antibiotic gut issues.
- What it shows: Gut microbiome balance, digestive function, inflammation, pathogens (bacteria, parasites, yeast).
- Why choose it: Ideal if you want a comprehensive view of gut health and digestion.
Learn more about GI360 Stool Test →
DUTCH Complete Hormone Test
- Best for: Perimenopause, menopause, PMS, fatigue, mood changes, sleep issues, HRT monitoring.
- What it shows: Oestrogen, progesterone, testosterone, cortisol rhythm, melatonin, hormone metabolism and neurotransmitter metabolites.
- Why choose it: Perfect for hormone balance questions and understanding how stress affects your health and hormones.
Learn more about DUTCH Complete Test →
Organic Acids Test (OAT)
- Best for: Fatigue, brain fog, low mood, ADHD/autism support, neurological issues, yeast or bacterial overgrowth.
- What it shows: Energy production pathways, nutrient metabolism, detoxification markers, oxalate levels, neurotransmitter metabolites, microbial by-products.
- Why choose it: Excellent for exploring gut–brain connections and hidden nutrient needs. A good functional lab test for children as it gives a broad overview with just one urine sample. Paediatric collection kits are available if your child is in nappies. Simply message us to request this when you place your order.
Learn more about Organic Acids Test →
SIBO Breath Test
- Best for: Daily bloating, excessive gas, IBS symptoms (diarrhoea, constipation, or alternating), poor response to elimination diets.
- What it shows: Hydrogen and methane gas patterns produced by bacteria in the small intestine.
- Why choose it: Focused, non-invasive way to check for bacterial overgrowth in the small intestine.
Other Tests to Consider
- Kryptopyrrole (Pyroluria) Test: Can help explain anxiety, addiction issues, mood disorders, poor stress tolerance or focus issues linked to zinc/B6 imbalances.
- Food Intolerance Testing: Highlights IgG food reactions that can contribute to bloating, fatigue, mood or skin issues.
View all functional testing options →
How to Choose the Right Test
- Start with your main symptoms: gut, hormones, brain/mood, or metabolism.
- Consider whether you need a broad overview (GI360 or OAT) or a focused test (SIBO, DUTCH).
- Remember: sometimes a combination of tests gives the clearest picture. For example:
- GI360 + SIBO = full gut overview
- DUTCH + OAT = hormones + energy/metabolism
- GI360 + Food Sensitivity = digestion + potential triggers
The Role of Interpretation
If you need help putting your test results into context, I can help. Working with an experienced clinical nutritionist can make the difference when it comes to interpreting and applying the results. I have a degree in Nutritional Medicine, an MSc in Public Health Nutrition and over 15 years experience in interpreting functional tests. I interpret results in the light of your history and symptoms, then create a tailored nutrition plan that helps you move forward. You can book an initial consultation here.
Ready to Find the Right Test for You?
If you’re confused about which test will give you the answers you need, fill in the contact form below with your symptoms and goals and we’ll get back to you asap.
