Background: Many epidemiological studies often face practical limitations in terms of acquiring biospecimens under identical conditions. Study design can require lengthy transportation of blood samples from regional locations to a central processing facility. Anecdotally, antibodies to infection are believed to be robust to variations in pre-analytic conditions. There is little information in the literature to support this statement.
Aim: To determine the stability of antibodies to cancer related infectious agents when a) subjected to prolonged storage at 4°C or room temperature (RT) prior to fractionation and, b) collected in different vacutainers.
Methods: 34 Cancer Council NSW employees provided blood samples in SST, EDTA, ACD and lithium heparin vacutainers. Samples were stored at RT or 4°C until centrifugation and fractionation within one hour of collection (day 0) and at daily intervals to day 6 and stored at -80°C prior to analysis. Median fluorescent intensity (MFI) values for antibodies to 42 recombinant fusion proteins of human papillomaviruses, polyomaviruses, Epstein Barr virus and Helicobacter pylori were quantified by bead-based multiplex serology.
Results: Mean MFI values for antibodies in lithium heparin plasma were the most stable (mean % change in MFI per day = 0.0% (95%CI[-1.1,1.2]). Mean MFI values for antibodies in EDTA plasma and serum (SST) decreased by 1.1% (95%CI[0.1,2.2]) and 0.7% (95%CI[-0.5,1.8]) per day, respectively. In contrast, mean MFI values for antibodies in ACD plasma increased by 1.5% (95%CI[0.4,2.5]) per day on average. Storage at RT led to an increase in mean MFI values, averaged across all antibodies, in all vacutainers. Mean MFI values increased the most for ACD plasma (4.6%(95%CI[0.3,9.1]) stored at RT.
Conclusions: Mean MFI values, averaged across all antibodies, for delays in processing vary according to vacutainer type and increase with pre-fractionation storage at RT. Vacutainer choice, processing delays and pre-fractionation storage temperature impacts on cancer risk factor analysis.