Dr. Blaney presented data, serum blood values mostly, from his own sizable cohort of MP patients. Using that data, he articulated a rationale for why 25-D is an inferior marker of inflammatory disease compared to 1,25-D. He showed how, among his cohort, measures of 25-D had a high level of variability and 1,25-D tended to be more consistent with disease status. One of his sickest patients, he reported, had a 1,25-D in excess of 100 pg/ml. Hopefully, his talk will challenge, in at least some small measure, doctors’ and researchers’ practice of testing only 25-D.