Infliximab and adalimumab are stable in whole blood clotted samples for seven days at room temperature

Abstract

INTRODUCTION: The biologic anti-tumour necrosis factor alpha (anti-TNFalpha) agents infliximab and adalimumab are monoclonal antibodies with binding specificity to TNFalpha, which are used for the treatment of Crohn's disease. Clinical response is varied from complete with mucosal healing, to primary non-response, loss of response and adverse drug reactions. Measuring trough blood levels of infliximab and adalimumab may guide clinical management. The sample handling requirements for infliximab and adalimumab were previously unknown. AIM: The aim of this study was to determine the in vitro stability of infliximab and adalimumab in samples stored for up to seven days at room temperature. METHODS: Samples were stored as clotted whole blood or serum at room temperature for up to seven days, before being frozen (-20) and analysed as a batch for either infliximab or adalimumab. RESULTS: No significant difference between the concentration of infliximab and adalimumab measured in samples stored as serum or whole blood for seven days at room temperature, as compared to baseline was found (t-test; infliximab: P = .35 [serum], P = .38 [whole blood]; adalimumab: P = .12 [serum], P = .49 [whole blood]). CONCLUSION: The stability of infliximab and adalimumab at room temperature for seven days allows samples to be posted direct from clinics and research centres to the analysing laboratory.