LC-MS/MS application for urine free pyridinoline and free deoxypyridinoline: Urine markers of collagen and bone degradation

Simultaneous measurement of two free pyridinium cross-links provides a valuable, cost effective assessment tool for use in the diagnostic work-up of patients with metabolic bone disease. Improvements in sample extraction efficiency have increased assay specificity and analysis throughput. The use of the fDPD:fPYD ratio can assist in the diagnosis of type VI EDS.