BGLAP and chronic kidney disease: Mean plasma total OCN concentration in controls was 9 ng/mL (± 4 ng/mL SD; n = 19), mean total OCN in stage 3 CKD patients was 11 ng/mL (± 5 ng/mL SD; n = 20), and stage 4 CKD patients had a mean total OCN concentration of 22 ng/mL (± 7 ng/mL SD; n = 6).