Interpreting Gluten Content Graphs on Product and Test Pages

Interpreting Gluten Content Graphs on Product and Test Pages

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The graphs presented on the product and product test pages may need a little explanation in order to reap the benefits of what they represent.  These graphs are presented for the purpose of helping you to make a quick determination whether a food product is sufficiently gluten-free for your own needs. The following types of graphs are presented on product pages:

  • Detectable Gluten Graph: This graph represents tests that simply try to detect gluten.  These tests may not have the ability to determine how much gluten is in the food.  The goal of a qualitative test is simply to provide a “yes” or “no” answer to the question of whether there is gluten present.  As a result, they are often designed to be very sensitive to gluten, and can sometimes detect gluten in quantities that some people would consider safe.
  • Quantitative Graphs: The other four graphs represent tests that are either quantitative or semi-quantitative.  A quantitative test is one that can tell you, with a good degree of accuracy, how much gluten a food contains.  A semi-quantitative test is one that cannot give you a firm quantity for how much gluten is present in a food, but it can provide an estimate as to whether the gluten content is above or below a particular threshold. Gluten content is measured in in PPM, or “Parts Per Million”.  If you’re unfamiliar with PPM, click here for an explanation.  The four quantitative graphs represent test results at four different PPM threshold levels:
    • 3 PPM: This graph represents a food’s estimated gluten content with respect to a 3 PPM threshold, based on test results.  The number of tests indicating that the food contains less than 3 PPM of gluten will be reflected here as a percentage.  Greater percentages mean that the product tested below 3 PPM more often.  3 PPM is very close to the lowest detection limit currently possible with gluten testing.  It is reasonable to conclude that foods showing 100% on this graph are probably very close to containing zero gluten.  They are also significantly below the 20 PPM that the FDA requires for a food to be labeled gluten-free.  When testing new foods that have not been previously tested on IITGF, I generally begin testing at this threshold.  Foods containing less than 3 PPM of gluten should be safe for almost all people with celiac disease.
    • 5 PPM: This graph represents a food’s estimated gluten content with respect to a 5 PPM threshold, based on test results.  The number of tests indicating that the food contains less than 5 PPM of gluten will be reflected here as a percentage.  Greater percentages mean that the product tested below 5 PPM more often.  Foods with 100% on this graph are likely significantly below the 20 PPM that the FDA requires for a food to be labeled gluten-free.  Foods containing less than 5 PPM of gluten should be safe for the vast majority of people with celiac disease.
    • 10 PPM: This graph represents a food’s estimated gluten content with respect to a 10 PPM threshold, based on test results.  As with the other quantitative tests, the number of tests indicating that the food contains less than 10 PPM of gluten will be reflected here as a percentage.  Greater percentages mean that the product tested below 10 PPM more often.  Foods with 100% on this graph are likely well below the 20 PPM that the FDA requires for a food to be labeled gluten-free.  Foods containing less than 10 PPM should be safe for the majority of people with celiac disease.
    • 20 PPM: This graph represents a food’s estimated gluten content with respect to a 20 PPM threshold, based on test results.  The number of tests indicating that the food contains less than 20 PPM of gluten will be reflected here as a percentage.  Greater percentages mean that the product tested below 20 PPM more often.  According to FDA regulations, any food that is labeled gluten-free, must contain less than 20 PPM of gluten.  If this graph shows 100%, and multiple tests have been performed, there is a good chance that this product is safe for consumption by most people with celiac disease.  However, you should be wary of any food with less than 100% on this graph.

Examples:

Example for the Qualitative test history graph

The graph highlighted in the image to the left is an example of the detectable gluten graph.  This graph indicates that three tests have been performed that could be considered qualitative tests (ie. Tests that look for gluten in any amount, and report its presence, but not its quantity).  Of those three tests, one of them yielded gluten-free results, meaning that 33% of the qualitative tests performed on this food product were deemed by the test kits to be gluten-free.  The remaining two tests indicated that the product was not gluten-free.

Examples for the 3 PPM, 5 PPM, 10 PPM, and 20 PPM test history graphs

The highlighted graphs above are examples of the four quantitative graphs.  These graphs are explained below:

3 PPM

The left-most graph on the bottom row represents tests that indicated a result relative to a 3 PPM threshold.  In this example, out of three gluten tests performed on this product, only one of those tests indicated that the gluten content was below 3 PPM.  That means that the other two tests found that there was gluten above 3 PPM.  That gives this product a 33% score at 3 PPM.  You could conclude that this product probably can’t be counted on to consistently contain gluten below 3 PPM.

5 PPM

The center graph on the bottom row represents tests that gave a result relative to a 5 PPM threshold.  In this example, out of five gluten tests performed on this product, three of those tests indicated that the gluten content was below 5 PPM.  That means that the other two tests found that there was gluten above 5 PPM.  That gives this product a 60% score at 5 PPM.  Again, you would probably conclude that this product can’t be counted on to consistently contain gluten below 5 PPM.

10 PPM

The right-most graph on the bottom row represents tests that are applicable to the 10 PPM category.  In the example, five pertinent tests have been performed on this product.  Four of those tests indicated that the gluten content was below 10 PPM.  That means that one test indicated gluten above 10 PPM.  That gives this product an 80% score at 10 PPM.  Once again, this product probably can’t be counted on to consistently contain gluten below 10 PPM.

20 PPM

The graph on the top right represents tests that apply to the 20 PPM category.  In the example, six tests were performed, and all six of the results indicated that the gluten content was below 20 PPM.  That gives the product  a ranking of 100% at 20 PPM.  The implication here is that the product seems to be fairly consistently below 20 PPM.

Interpretation

Looking at the above graphs can give you some insight into whether the tested product is something you want in your diet.

If you believe your sensitivity to gluten is typical of most people with celiac disease, you can probably assume that you are able to tolerate foods that contain gluten in concentrations below 20 PPM.  Studies have shown that for the majority of people with celiac disease, 20 PPM is an acceptable threshold.  Most celiacs who keep their gluten intake below this level should see no adverse effects.  Since this product tested gluten-free at 20 PPM or less in all of six tests, that gives you a pretty good idea that it is probably relatively safe for you if you are, indeed, typical of most celiacs.

On the other hand, if you feel that you are more sensitive than most people with celiac disease, or if you’re trying to avoid as much gluten as possible, you may want to steer clear of this product.  At 10 PPM, it appears the prospects were a little hit and miss.  One out of five tests performed came back indicating gluten above 10 PPM.  Now, since the 20 PPM graph shows 100%, you can probably assume that the one single test in question likely came in between 10 and 20 PPM.  So, if you’re just slightly more sensitive than others, you might still be okay with this product.  Or maybe not.  Unfortunately, because sensitivity is highly subjective, each person must decide where their own thresholds are, and adjust accordingly.

Now, if you believe that you are highly sensitive—significantly more so than the vast majority of celiacs out there—then you should probably be looking exclusively at two graphs: The Qualitative graph and the 3 PPM graph.  If you are indeed that sensitive, you should unquestionably avoid any product that doesn’t have 100% on both of those graphs.  These two graphs represent the most stringent thresholds. As such, if you’re highly sensitive, or wanting to avoid any and all gluten, these two graphs, above all the rest, will probably give you the best shot at doing so.

A Word on Test Repetition

Repetition of tests is an important factor to consider when looking at these graphs.  Be forewarned that, while the accuracy of the tests I use is quite good, no test is 100% accurate.  Many factors can affect the outcome of a test, and it’s not outside the realm of possibility that some test results could be wrong.  This is where repetition comes in.  If multiple tests have been performed on a product, and they all agree on the gluten status of that product, then it’s far less likely that the result is in error.

Cover Your Bases

As I state repeatedly on this site, please do not base your dietary decisions exclusively on the information presented here.  Products and ingredients can change without warning, and the testing on this site may not always be in sync with those changes.  Not only that, but testing is not always 100% accurate.  Always read labels!  Even if you know it was gluten-free the last time you read the label, read it again!  For safety’s sake, never make assumptions!

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