An oncologist is key in diagnosing WM. For me, I was diagnosed as IgM MGUS (Monoclonal Gamopathy of Unknown Significance) first. This meant that I was over producing IgM white blood cells. Over several years they watched those numbers and did several bone marrow biopsies. Once the IgM cells (adult cells) had infiltrated the bone marrow to a number grater than 10%, I had crossed over to WM. This also included other symptoms that I had: heavy night sweats, peripheral neuropathy, shortness of breath, headaches, extreme fatigue. The critical tests to watch initially is the blood-work tests. This will tell the initial story, and if needed then a bone marrow biopsy.