Dr. Diana, Sorry to hear that you are going through such a frustrating time with the muscle wasting. Having a diagnosis would make things so much easier when we try to deal with our illnesses(both for our sanity and obviously for treatment). I agree that trying out the easy stuff, working on B12 deficiencies if that’s in order, is a better way to start then venturing down the tricky path of eosinophilic disorders.
Regarding B12 testing, glad to hear that Quest has added Holo-TC to their blood test list. I’m hoping that it is offered here in Canada as well. Too bad that Quest doesn’t also offer the MMA testing (either urine or blood) but I suppose it’s cost prohibitive.
I found this short concise explanation (in comparison to the lengthy, in-depth explanations often found) of Active B12 for anyone interested –
One of the biggest problems with diagnosing B12 deficiency is that the conventional serum B12 test that most doctors run only picks up a small fraction of people who are actually B12 deficient. This test measures the total amount of B12 in the blood, and does not rule out functional B12 deficiency. (1) More sensitive markers for B12 deficiency are now available, including methylmalonic acid (MMA) and holotranscobalamin II (holo-TC). MMA is converted to succinic acid via an active-B12 dependent enzyme, so if MMA levels are high, it suggests that active B12 is lacking. Holotranscobalamin II is composed of vitamin B12 attached to transcobalamin, and it represents the biologically active part of B12 that can actually be delivered to the cells and perform all of the functions of B12. Studies using these newer methods report much higher levels of deficiency than studies using only serum B12.