R5 ELISA Test Results for Gluten-Containing Products Testing “Low Gluten” & “High Gluten” Using the Nima SensorTricia Thompson
Bottom Line: Based on testing done to date by Gluten Free Watchdog, products testing “low gluten” using Nima tested from below the limit of detection of 1 ppm gluten up to 18,963 ppm gluten using the R5 ELISA. Barley flour also tested low gluten. Based on these results it is difficult to assess the meaning or understand the usefulness of a “low gluten” Nima reading.
Why did we test gluten-containing products: We tested a variety of gluten-containing products out of curiosity to see how they would test using the Nima and to help determine whether “low gluten” and “high gluten” results correlated with R5 test findings.
Gluten Free Watchdog also tested wheat flour, rye flour, and barley flour using the Nima. Approximately the same amount of each type of flour was tested. The samples were not diluted with water.
Barley flour: “low gluten”
Rye flour: “high gluten”
Wheat flour: “high gluten”
Comparison testing: All product testing with the exception of the flours was done by Bia Diagnostics, LLC.
Findings: To view data table click GlutenFreeWatchdogTableBiaNimaR5Redacted
Information on the meaning of low gluten and high gluten: According to the graphic posted on the Nima website entitled, “Understanding Test Results with Nima” a “low gluten” result means that “Gluten at levels above 20 ppm was detected, most likely due to cross contamination.” The range given for “low gluten” is 20 ppm to 15,000 ppm. A “high gluten” result means that “Gluten at 100 ppm or greater was detected in the sample.”
- 100% barley flour tested “low gluten” using the Nima.
- Barley grain and barley flour have both resulted in “low gluten” readings when tested by Gluten Free Watchdog. This finding raises the question of whether relatively low levels of barley contamination (as compared to barley grain/flour) would be detected in a sample when tested using the Nima? Gluten Free Watchdog has observed first hand that the main contaminant in some grains, legumes, and finished grain-based products is barley.
- In this analysis, products testing from 819 ppm to 18,963 ppm gluten using the R5 ELISA tested “low gluten” using the Nima and a product testing below 100 ppm gluten using the R5 ELISA, tested “high gluten” using the Nima.
- The Nima graphic referenced above suggests that a “low gluten” reading is most likely due to cross contamination. Keep in mind that all the products included in this round of analysis contained gluten as an ingredient.
- Including our prior test report on foods labeled gluten-free or appearing to be free of gluten-containing ingredients (available at https://www.glutenfreewatchdog.org/news/products-testing-low-gluten-using-the-nima-sensor-test-less-than-5-ppm-using-the-r5-elisa-false-positives/), the range of products testing “low gluten” to date includes:
- A certified gluten-free product testing below the limit of detection of 1 ppm using the R5 ELISA.
- A product containing wheat flour as the second ingredient after spices and testing at 18,963 ppm gluten using the R5 ELISA.
- 100% barley flour.
Gluten Free Watchdog will continue to evaluate the Nima.