Influence of the sample matrix on the stability of beta-CTX at room temperature for 24 and 48 hours.

The measurement of β-C-telopeptides of type I collagen (β-CTX) reflects the rate of bone resorption in a variety of metabolic bone disorders and it is increasingly used to assist diagnosis and follow-up of these pathologies. Since preanalytical biases in the results of this marker can decrease its clinical usefulness, specific stability studies should be developed to prevent that inconsistent results of laboratory testing might affect patient health and waste economical resources. Three blood samples were simultaneously collected without venous stasis into evacuated tubes containing no additives, K2 EDTA or lithium beparin, from 23 out-patients referred to our phlebotomy service for routine laboratory testing. After centrifugation and separation of the specimens, a first aliquot was immediately analyzed, whereas a second and third aliquot was processed after a 24- and 48-hour storage at room temperature (21 °C). β-CTX was assayed on the automated electrochemiluminescence analyzer E170....