Preanalytical factors affecting the stability of matrix metalloproteinase-2 concentrations in cerebrospinal fluid

Abstract

Background Matrix metalloproteinases (MMPs) are crucially involved in central nervous system inflammation. This study assesses preanalytical factors on MMP-2 concentrations in cerebrospinal fluid (CSF). Methods The concentrations of MMP-2 in CSF obtained from 13 patients were measured using ELISA. Identical measurements were done from the samples of the CSF from the same collection that were successively stored in glass tubes, stored at room temperature (21 °C), or refrigerated (4 °C) and frozen and thawed five times. Results After 48 h of storage at room temperature and refrigeration, there was a significant decrease in the concentrations of MMP. Sample storage in polypropylene or glass tubes led to a comparable decrease in MMP-2 concentrations. The freeze–thaw cycles, which were repeated five times, did not significantly affect MMP-2 concentrations. Conclusions The storage of CSF at room temperature or refrigeration significantly decreases MMP-2 concentrations. Subsequent freeze–thaw cycles or glass tube material did not influence MMP-2 concentrations. Samples of CSF should be frozen immediately after collection to ensure accuracy of MMP measurements.