Candida infections: Three Testing Options

candida infections three testing options

Candida is often the first thing that patients think has gone wrong in their gut. Frequently it is more complicated and often involves bacterial overgrowths, enzyme dysfunction leading to food intolerances as well as potential fungal overgrowths. That said, the more functional testing I do the more I realise that fungal and mould overgrowths and infections can be the major root cause for ongoing digestive symptoms. Today we are exploring three different testing options for candida overgrowths.  

Candida infections 101 

For a quick primer on Candida overgrowth symptoms and how it can damage your digestion check out a previous article – Candida infections – when harmless becomes harmful.

I have also put together a decent intro to Candida infections below 

As a quick summary. Candida can be a healthy resident of a balanced microbiome. When given the right environment candida can overgrow and cause a whole range of digestive issues including

  • Oxalate sensitivity symptoms (more than we can list but the big one here is joint pain and sore muscles)
  • Fatigue to due Candida’s ability to negatively impact mitochondrial function 
  • Bloating and abdominal pain 
  • Leaky gut
  • Itchy anus 
  • White coating on the tongue  

Testing options for Candida Overgrowth

In my practice I have used 3 different testing options to screen for candida infections growing in the gut. 

Before we dive into each one and end with my current preferred method to test, let me just say no test is perfect. I have seen good tests miss Candida more than once. For this reason I prefer the organic acids test.

More on that later.

Stool Test for Candida

Let’s start with the most popular approach to testing for candida in natural health clinics.

Stool testing has come quite far from the culture and microscopy days. Now we have advanced DNA based tests like the Complete Microbiome Mapping stool test and Microba that can screen for candida in the large bowel. 

A stool test showing a Candida albicans overgrowth in the large bowel
A stool test showing a Candida albicans overgrowth in the large bowel

When I see a result of a candida overgrowth like the one above I make sure to explore the relevant symptoms with the patient carefully. Is candida a major player in their symptoms? 

For the most part I think that stool tests under report on the fungal infection front. I’m still not 100% sure why that is but the case study I share at the end of this article helped me to understand this stool test limitation.

Summary – Stool testing for candida is a common practice but is less reliable in my clinical experience.

Blood test for candida

Another option that is used to screen a patient for candida is antibody testing. I find that some patients’ doctors have recommended this testing option. 

The main issue here is that the person’s immune system has to have recognised candida as an invader and mounted an attack on it. This is a prerequisite to a positive test. 

Below we see a blood test right on the line for candida overgrowth and we are left with the question – is candida an issue for this person?

blood testing for candida
blood testing for candida

Summary – In my experience antibody blood testing for candida is more commonly practiced by doctors. I find it quite unreliable. 

Organic acids testing for candida

Finally we come to my favourite way for testing for fungal overgrowths.

The OAT test (organic acids test) is my new preferred test for most of my patients. I have seen such significant results from this test that help to steer the treatment that I am considering making it a prerequisite test for all of the people I work with.

This test screens for bacterial and fungal overgrowths, metabolic and mitochondrial function, the state of your neurotransmitters, your ability to detox and even nutrient status. 

Back to candida overgrowths. Below we can see an elevation in arabinose, a marker of a fungal overgrowth. This is the marker I frequently see elevated. While it doesn’t specify candida it does indicate probable fungal overgrowths. From there we can work backwards to symptoms and history to really reinforce the possibility. 

OAT test from Great Plains Laboratories showing elevated arabinose
OAT test from Great Plains Laboratories showing elevated arabinose

When I see an elevation in arabinose and carboxycitric acid like the image below it reinforces the fungal overgrowth theory.

OAT test from Great Plains Laboratories showing elevated arabinose and carboxycitric acid
OAT test from Great Plains Laboratories showing elevated arabinose and carboxycitric acid

I am sure you have picked up on the vagueness in my descriptions.

With OAT testing I find myself using words like possibility and fungal overgrowth rather than the specific species. This is because the OAT test won’t tell you exactly what microbe you are dealing with. 

At first I considered this a major issue and disregarded OAT testing as an option. Now I have come to see it as one of the most insightful tests on the market. 

Here is why.

Organic acids testing results will give us an insight into how the body is compensating due to a fungal overgrowth. These include oxalate load, mitochondrial function, neurotransmitter imbalances, detox pathways and even certain nutrient deficiencies. 

Excessive oxalate production is often a consequence of a fungal infection or overgrowth as seen in the test result below.

OAT test from Great Plains Laboratories showing severe oxalate overload
OAT test from Great Plains Laboratories showing severe oxalate overload

Candida has the ability to drive excessive oxalate production via the isocitrate lyase enzyme which hijacks isocitrate in the human krebs cycle, converting it to glyoxylate and then on to (extra!) oxalates.

Here is why we see joint pain and muscle soreness as a consequence of a candida overgrowth. The oxalate load, causing these symptoms, is merely a consequence of the fungal overgrowth!

So with the example above we know there is a fungal overgrowth and that the oxalate load is extreme. Treatments for this patient included lowering her oxalate intake from her diet, citrate based minerals to bind and detox oxalates and finally, antifungal herbs.

Summary – While OAT testing won’t identify the exact species overgrown, it will reliably tell you if there is a fungal overgrowth and how the body is compensating to deal with it.

A case study comparing testing options for candida

To really illustrate the value of the OAT test I want to share a case study from a patient of mine using the three testing options listed above.

She came to me with stool test results from the Complete Microbiome Mapping test from Nutripath. These results showed zero candida. Not her issue right? 

From her symptoms and her intuition that there was a fungal issue going on the serum candida antibody test was ordered. Here we see a mild elevation in IgG but nothing to be concerned about.

As her treatment unfolded and our suspicion of some fungal overgrowth persisted, I recommended the Great Plains Organic Acid test currently my top choice for OAT testing. Here we see clear markers for aspergillus and candida.

After two false negative tests it turns out this patient was mould/fungi affected after all!  

Test don’t guess

I have bounced between the testing and not testing approach for some time now. I think it was because no test is perfect and I frequently found that the test results didn’t change my approach. 

All of that is in the past now that I have dug down and really worked out how to interpret the OAT test. It is a never ending journey. I joke to my patients that you need three different degrees to really understand what this test reveals, then I remind them that addressing the root cause, often gut imbalances, can help to resolve chronic illness.

Since I have started using the OAT test on a weekly basis I have found a number of candida overgrowths that I would have missed using stool testing and symptom presentation alone. 

I hope you learned something new! Leave a comment below. If you think you may have a candida overgrowth then consider working with me here at Byron Herbalist

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  1. What about bioresonance tests that use your DNA sample like saliva, hair & nail? I’ve seen it show parasites, mold, candida & other toxins in body while stool and OAT tests don’t.

    1. Great input! I like to use published and peer reviewed science to help guide my approach. I haven’t done a deep dive on bioresonance but don’t believe there has been much published on its use (happy to be wrong there!).

      That isn’t to say there is no value in that approach. The end goal is feeling better, whichever route gets you there that doesn’t cause harm I’m all for.

  2. Very interesting. My 24 year old daughter has been dealing with non stop digestive issues for four months. She experienced similar issues in 2018 which disappeared after two months (multiple tests did not find a cause). We live in the United States. What is the best type of professional to see who can test for candida? All of the symptoms you mentioned she is experiencing.

    1. Hi Vicki, I would recommend seeing a good functional medicine practitioner or naturopath/herbalist. Often the best are naturopath/herbalists that work in functional medicine too.

      1. I have seen one practitioner in particular talk about immunoglobulins in SIBO treatment (not first live treatment) but for challenging cases. There are a few studies on it. Do you have experience with utilizing immunoglobulins.

  3. Hi! I am doing research on behalf of my 14 year old daughter. About two years ago, she came down with a rash…head to toe. We tried everything until a functional dr. asked to also look at her tongue…. coated in white. Candida was blamed. She went on a two week diet to eliminate all forms of sugar, took antifungals and probiotics, and it went away… or at least we thought. The last two years she has gained weight like crazy and has been super tired a lot. Even with trying to eat healthy and swimming several days a week, she was still struggling. I had blood tests done and now we find out her thyroid is out of wack and has been diagnosed with Hashimoto’s (which does run in my husband’s family). Have you had experience with the candida/hashimoto’s connection? I am wanting to have her tested for Candida but not sure which test would be best. Any thoughts?

    1. Yup I have seen fungal overgrowths impact the thyroid in at least 3 patients. There could be an fungal/oxalate connection here or possibly leaky gut leading to an overactive immune imbalance. I frequently recommend the OAT test from Great Plains as a first test for more complex cases. It is hard to interpret for beginners but SO darn helpful in many patients cases.

  4. Hi Todd,
    Would the Organic Acids Test detect Candida Krusei (Pichia Kudriavzevii)?

    And what specialized test could find out which specific Candida type is detected with the OAT?

    thanks in Advance

  5. Hi! I was wondering what you think about a GI MAP test showing no candida but the OAT markers being elevated? Thank you for your help!

  6. Hi Tod
    Do you treat Candida with anti-fungal medication like fluconazole or such other?
    if so would it be ok to take a dose for a few days given they are available over the counter,

    understanding this is not considered medical advice.

  7. So would an OAT be able to distinguish between a systemic Candida infection and mitochondrial dysfunction? I started detoxing unexpectedly several months ago due to a single dietary change, and at first I thought it was due to a buildup of metabolic waste. More recently I’ve come to suspect that it’s Candida, and knowing which it is (or neither) would help me decide how to proceed from here.

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