I appreciate the original article, others like it as well, and this educated commentary.

If the discussion is reaching clinicians in Genetic and Metabolic Diseases I am pleased. Some clinicians, not necessarily metabolic disease specialists, have been using tests of this sort, which may be provided by specialized commercial laboratories, often as "nutritional studies," not necessarily provided by the same laboratories that metabolic diseases specialists would use. And, those clinicians are not necessarily having their test results read by metabolic diseases experts. We need such expertise: as the author points out there are many caveats and insights which can be shared. Whether metabolic testing rules in or rules out the possibility of a metabolic etiology, or component, of any kind is a plus to our ultimate understanding of both of chronic fatigue syndrome and fibromyalgia disorders.

One immediate question is whether or not this sort of testing (properly done) should be encouraged among these patient groups who often share many symptoms. And the question of "if not" then "why not" should also be debated. When people have been sick this long and sensitive, clinically well validated, avenues of further investigation are available, why not take a chance and explore them. The testing is not invasive or even overly expensive. It doesn't seem however that most clinicians treating chronic fatigue syndrome and/or fibromyalgia patients are inclined to use them. This sort of testing is not well known to everyone and many regard it as outside of their expertise and area of comfort.

It may also be helpful to consider the type of provocation testing that may shed further light on any observations. At least follow-up is possible in the hands of the right people.

A friend once commented to me that he felt his reading of thousands of negative results was crucial to his spotting the few truly abnormal ones. That comment reflects the true learning of one's craft. I hope this subject will enter the Genetic and Metabolic Diseases practice for whatever knowledge can be gained. This is a desperate situation for so many people who have lingered, are lingering, with these debilitating diseases.