My battle continues. Rheumatology have examined me and written a letter to my Dr saying I have some signs of fibromyalgia but not enough to seek group treatment as it doesn't stop me being active. However blood tests have shown isolated low IgM at 0.3 (NR 0.5 - 1.9). They've asked for serum electrophoresis, urinary bence jones, and serum free light chains and I have an appointment next week with GP to discuss. Has anyone else experienced low IgM and what could cause it? Is it common with CFS/ME/fibro sufferers or could it be pointing to something else? Google says it's uncommon and so I can find little info on it. Worryingly the tests ordered seem to test for some very nasty things indeed which I'm trying to ignore for now....