Nima Update: Limit of Detection
Post date: July 12, 2017
The following email was sent to subscribers to Gluten Free Watchdog this morning (July 12, 2017):
Dear Gluten Free Watchdog community,
This email is primarily for those of you who test products using Nima or are interested in this device.
We are receiving increasing requests both from inside and outside the GFWD community to test products that have detected gluten using Nima. As you know we have tested a few of these products when the integrity of the food has been maintained (e.g., the product is in original packaging and steps have been taken to prevent contamination).
Nima has not yet published a validation report in the scientific literature. However, Nima is stating publicly that when a food contains a level of gluten below 2 parts per million, the Nima device is reporting gluten detected approximately 8% of the time. For more information seehttps://nimasensor.com/science-nima-understanding-device/
In addition, a new ELISA appears to have been developed using at least one of the antibodies used by Nima (Nima reports their antibodies as 13F6 and 14G11 and the ELISA manufacturer reports their antibodies as 13F6 and 14F11). The limit of detection for this ELISA is reported as 0.36 parts per million of gluten. Information about this ELISA was presented at the IAFP conference yesterday via two poster presentations. Validation data for this ELISA involving a multi-laboratory ring trial has not yet been reported in the peer-review scientific literature. For more information about this ELISA seehttp://www.biofronttech.com/product/food-safety-monotrace-food-allergen-elisa-kits-gluten/gluten-elisa-kit-48-wells/1704141/
What all of this appears to mean is that when using the Nima you may get a gluten detected result when the product contains a very low level of gluten (below 2 parts per million). In our testing, 5 products tested low gluten using Nima and below the limit of detection of 1 part per million using the R5 ELISA. However, it remains unclear whether these results are true false positives (no gluten present) or due to a low limit of detection. All of these products have a similar consistency so there may be matrix issues involved.
At this time we will no longer be accepting from consumers products that have tested “gluten detected” using Nima. It is the responsibility of Nima to accurately convey to their users the likelihood that a certified gluten-free product containing a level of gluten below 20 ppm, 10 ppm, or 5 ppm may test “gluten detected” using Nima.
For information about our test findings using the Nima and our current position on consumer use of the Nima, please seehttps://www.glutenfreewatchdog.org/news/gluten-free-watchdogs-position-statement-on-consumer-use-of-the-nima-sensor-to-test-food-for-gluten/
Tricia Thompson, MS, RD
Founder, Gluten Free Watchdog, LLC
Important to consider: A device that has a low limit of detection “some of the time” may result in products with lower levels of gluten testing “gluten found” and products containing higher levels of gluten testing “smile”. In other words, a product that has a level of gluten below 2 parts per million may test “gluten detected” and a product that has a level of gluten of 19 parts per million may test “smile”.