Are You Using the Best Test for Vomitoxin?

Mycotoxin presence in feedstuffs may be unavoidable at times; having confidence in the testing methods you use to measure those levels doesn’t have to be. High mycotoxin levels in grains can negatively affect the overall health and performance of animals, resulting in a loss of profits. To make informed feeding decisions, it is crucial to accurately and precisely test grains for mycotoxins. With many lab and quick test options currently on the market, it can be difficult to determine which is the most reliable. With this issue in mind, NutriQuest performed a proficiency test to determine the variability and accuracy of labs and quick tests currently on the market for the analysis of DON (Deoxynivalenol or vomitoxin) in corn and DDGS.

Testing Procedure
The accuracy and precision of five quick tests and seven labs were analyzed in a proficiency test. Two subsamples of eight corn and DDGS samples were tested on each quick test and sent to each identified lab for analysis. These subsamples were then tested in duplicate, for a total of four readings per initial sample.

Quick Tests



Midwest Labs


Envirologix QuickScan DON FLEX


Romer Labs

Neogen Reveal® Q+ for DON



Romer AgraStrip® DON WATEX®

Trilogy Labs


Vicam DON-V®


Variability within quick test/lab was measured by calculating the coefficient of variation (CV) among the four readings per sample. Accuracy was measured by calculating z-scores using the Virginia Tech mean and standard error for the same samples, and using Youden plots. For CV and z-scores, lower values indicate less variability and improved accuracy, respectively.

The results are in – Large variation exists among Quick Tests and Labs

For the five quick tests analyzed, average CV ranged from 7% to 22% in corn samples and 3% to 20% in DDGS samples; two systems had CV below 10% for both commodities. Average z-scores in corn ranged from 6.97 to 42.80; only two quick tests had average z-scores for corn under 10. Average z-scores for DDGS ranged from 6.67 to 11.51, with three quick tests having average z-scores below 10. It was common for quick tests to yield results varying 3 ppm for the same sample in both corn and DDGS. Youden plots confirmed that the quick tests with high CV and z-score assessments had either random or systematic errors in the systems, resulting in inaccurate and/or imprecise results.

Quick Test Values for DON Levels

Quick test for DON

*Data point for Quick Test 3, DDGS sample 8 is not present as the sample read above the quick test’s limit of detection.

In the seven labs analyzed, average CV for corn ranged from 16% to 60%, and from 2% to 10% in DDGS. One lab had an average CV at or below 10% when averaged for both commodities. Corn average z-scores ranged from 5.04 to 9.16, and DDGS average z-scores ranged from 1.11 to 16.39. One lab reported average z-scores below 5. It was common for labs to yield results varying 2 ppm for the same corn sample, and up to 6 ppm for the same DDGS sample. Youden plots confirmed that labs with high z-scores exhibited high systematic error, leading to inaccurate results.

Lab Values for DON Levels

Lab values for DON

*Data point for Lab 4, corn sample 4 is not present as the corn sample could not be tested at that lab.

Why does it matter?
The DON proficiency test demonstrates that when testing for mycotoxins, the quick test or lab used largely impacts the reliability of the data. This is especially concerning seeing that a 2 ppm difference considerably changes how grain is handled.

Editor’s Note: If you’d like to learn how specific quick tests and labs performed in this evaluation, visit



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Submitted by aa on Wed, 01/24/2018 - 07:22