A few weeks ago, we featured an article about the rapid gluten test RIDA®QUICK Gliadin. This handy gluten test strip can be used for swabbing surfaces directly on-site without any equipment, providing results in only 5 minutes. After sample preparation, the test strip can also be used for testing raw and processed foods. So, the test certainly is practical – but how good are the results? This was recently reviewed by AOAC in an international ring trial.
If you can’t tolerate gluten, you need to be able to rely on the manufacturer to only label foods as gluten-free if the really are. For this reason, raw goods, production areas and finished products must be tested for gluten contamination. Many manufacturers of gluten-free foods use rapid tests (such as our lateral flow test RIDA®QUICK Gliadin) for their allergen management. In other areas, too, the demand for rapid tests is large. However, a frequently asked question refers to the reliability of those tests: Is a rapid test really able to provide reliable results in such a short time?
Generally it can be said that a lateral flow test is a very precise test method. The RIDA®QUICK Gliadin test strips show a good correlation with the official type I method according to the Codex Alimentarius (which is an ELISA test using the R5 antibody). Indeed, the RIDA®QUICK Gliadin achieves good scores both in specificity and in sensitivity:
- The monoclonal antibody R5 reacts with gluten from wheat, rye and barley.
- There is no cross-reactivity with soy, oats, corn, rice, millet, teff, buckwheat, quinoa and amaranth.
- The detection limit is 1-2 μg gliadin per 100 cm² on surfaces, 2.2 mg gliadin per kg for raw goods and 3.1 mg gliadin per kg for processed foods.
However, if you want to know whether a test method is reliable, perhaps the most important argument is validation. This is the proof that an analytical method is suitable for its specific purpose and that it meets requirements in terms of accuracy, precision, robustness, specificity, selectivity, reproducibility etc. – and this proof is what our rapid gluten test has now officially received: The AOAC INTERNATIONAL, one of the most important organizations for the validation of analytical methods, has reviewed the RIDA®QUICK Gliadin in a ring trial involving 18 laboratories. As a result, the RIDA®QUICK Gliadin has received validation according to AOAC-OMA (“Official Methods of Analysis”) for the analysis of corn products. Our test method was adopted into the AOAC Methods Board as a First Action Official Method under the number 2015.16.
Besides our lateral flow test, our two ELISA tests RIDASCREEN® Gliadin and RIDASCREEN® Gliadin competitive have already been validated, too. The validation according to AOAC-OMA is recognized world-wide and we are very pleased that our rapid gluten test meets the AOAC’s high requirements.