Free Content Series

Dr. Anderson regularly publishes free content.
1 Jan 2019

Mycotoxin Testing Methodology and Sensitivity – Specificity: Clinical Experience and Thoughts

All the above (or almost all) reference ELISA based systems [Real Time etc.] or relatives. We had some Q&A on this in that webinar after AAMP Portland 2018 as it isn’t so evident sometimes when labs do different methodologies. I had this SUPER long winded answer – BUT- thank god the PhD from Great Plains said it already. My main points would be:

  1. It’s like heavy metal testing, no perfect test and in the case of HM until we started norming to NHANES no good reference ranges (thank god that’s at least fixed).     
  2. There, in some patients, can be HUGE differences in sensitivity and specificity between same sample processed with ELISA and LC-MassSpec.    
  3. Like all tests one has to evaluate the “sick user” effect [we usually test folks with symptoms and not huge randomized communities as clinicians – so we get more true positives in most testing]. This also leads to re-assessing in cases of negative tests [is it the test or is something else causing the issues?]    
  4. In my opinion [unless patients want to do both an ELISA and LC-MS test which may be the ‘best’…] for reasons stated by Dr. Pratt-Hyatt who I know and believe to be reputable I personally use LC-MS for mycotoxins and trust GPL because the norm out the false positives better than any other lab. So this in a sense helps the test validity concerns in my practice and clinical experience (remembering no test is perfect, which is why we are doctors and not technicians.) Yes Matt works for GPL but I would have stated every point he does and I don’t work for them (I even have to buy my own test kits for my family…)   *Note the links mentioned can be opened on the GPL site.
  5. I’m not opposed to ELISA based testing. It is just in this instance with the lab state of the art as it is my current choice is GPL and LC-MS.                                                

QUOTE:  “Since we released our new GPL-MycoTOX Profile, we’ve received many questions about what the differences are between the types of mycotoxin testing available, why we use the technology that we do (LC/MS), and why we believe that technology is superior.  I wanted to share our feedback about that with you, including support data in the form of some split sample reports.


ELISA testing is notorious for false positive readings.  ELISA principal is a lock and key activation. If any molecule fits the lock then the result shows up positive.  One of the criticisms often heard about mold testing is the over-abundance of positive results. The literature backs up this observation with findings that show inferences that cause false positive results.  At Great Plains, we use LC/MS, not ELISA. LC/MS separates out molecules by their chemical properties and measures their mass, so we get a definitive answer for every sample. We also use internal standards in every sample to give a definitive quantitative reading.


There are many factors that could influence the value for any urine test, including how recent the exposure was, how much the patient is detoxifying, and how much liquid the patient drank the night before giving the sample.  We are able to correct for the third of these reasons by measuring the amount of creatinine in the sample, which compensates for how diluted the sample may be. A particular sample one of our practitioner clients asked us about was more concentrated than most (creatinine was 166 mg/dL).  If the value was 80 mg/dL, then the value would have been doubled. This allows us to mitigate one factor that can cause mycotoxin test values to fluctuate.

We have received a couple dozen results from patients that run a test for mycotoxins from another lab, then have run our test.  We have seen the gamut of results such as their previous test coming back negative and ours is positive (see examples here – Patient 1 with GPL and Patient 1 with RTL), both tests were positive (see example here — Patient 2 with GPL and Patient 2 with RTL), and values where the patient was negative on both.


In our experience, no patients are “normal” when it comes to toxins, including mycotoxins.  We see mycotoxin in almost every patient, but we have set our reportable limits to only patients that we feel have abnormal amounts of mycotoxin in order to not alarm patients.  We have followed this up with a study of 50 patients with mycotoxins. If you look at this file, we did a comparison of patients with mycotoxins to patients without mycotoxins. We see numerous values elevated on our Organic Acids Test (OAT) in the mycotoxin positive individuals, demonstrating that our test can predict health problems for individuals.  We will soon have more information available about the connection with specific fungal markers on the Organic Acids Test

Please let me know if you have any questions about our GPL-MycoTOX Profile and we look forward to our continued work with you.”

Matt Pratt-Hyatt, PhD – Associate Laboratory Director