Relationship of 24 h urinary calcium excretion to serum 25-OHD (panel a) and 1,25-(OH)2D (panel b) in patients with sarcoidosis (US and IT combined). There was no significant difference between those with or without a history of nephrolithiasis (p=0.901 and 0.332, respectively). 1,25-(OH)2D, 1,25-dihydroxyvitamin D; 25-OHD, 25-hydroxyvitamin-D; IT, Italy; US, USA.