Mercury challenge misunderstandings: A guide especially for parents new to autism
One of the popular theories in the US, is that autism is caused by one or more forms of mercury. Where the mercury comes from depends on who you talk to, vaccines, dental fillings, fish, lights, computer screens, forest fires, and cremations have all been named as suspect. That may seem tricky enough, but the real question is in how children diagnosed with autism deal with the mercury.
Some sources claim that children diagnosed with autism are poor excretors of mercury. In other words for some reason they don’t get rid of the mercury their body accumulates (either in a fast or slow way) and that it poisons them and results in autism. For this group the advocates claim that mercury poisoning is difficult to assess. They may recommend assessing other biological factors as evidence. Or they may recommend a challenge (provoked) test for mercury.
Just to be clear, a provoked test is when a chelating agent is given to the patient and then the mercury test is administered. Some chelating agents bind to mercury and/or other heavy metals making it much more likely that they will be cleared from the body. This step is important for advocates of the poor excretor hypothesis, because they argue that the chelating agent captures mercury in the body. An increase between a non-provoked test and a provoked test is evidence of this according to certain parties. Or even without this non-provoked test, a provoked test that comes back in an elevated range can be evidence of this all by itself. However, others who advocate a mercury etiology of autism theory do not seem to put stock in the poor excretor theory. They advocate straightforward testing without a provoked test.
For a parent considering heavy metals testing a good first step is to decide which variant you believe in. These theories cannot both be true, they are exclusive. Children with autism are either poor excretors or they are not. And while some might try to be ingenious and claim that sometimes it is one and sometimes it is the other, I would ask the reader to decide whether this is truly a valid argument.
If a parent decides that the poor excretor hypothesis is unlikely, then there is no need for a provoked test.
If on the other hand a parent decides the poor excretor hypothesis is valid then a provoked test may seem reasonable. This is where my concerns begin.
My core concern is this; there is no mercury scale that was normalized with participants who were first given a provoking agent. This means that any of the provoked measurement will have to be compared to a scale established only with non-provoked samples. This is innately invalid, and yes, invalid is the right word here.
This is why: When one wants to establish a statistical scale, one must first create the conditions under which data will be collected. After data are collected a mean (average) is determined as is the standard deviation, which is simply a statistical way of determining how far away (in either direction) a given score is from the average. However, if you try to compare a given score taken under different conditions from how the scale was formed, it is no longer meaningful.
These data taken under different conditions were not included when the mean or standard deviations were calculated. For them there is neither mean nor standard deviation. The comparison is meaningless, and there is no way right to compensate for this problem at the moment. And while this may be a standard practice for many labs and practitioners, anyone who tells you these tests can be used to determine mercury poisoning is not using any recognized standard of science or statistics.
If you are a parent please be aware of these facts when you consider a provoked test.