Preanalytical Stability of Antibodies to Pathogenic Antigens

Background: Serological testing for antibodies against epitopes from pathogens is a valuable tool for investigating the relationship between infection and disease. This study comprehensively evaluates the impact of pre-analytic variation on antibody seropositivities to a selected set of antigens arising from delays in processing of blood samples, pre-processing storage-temperature and vacutainer-type. Methods: We assessed peripheral blood collected from 29 volunteers in four different Vacutainer® types (ethylenediaminoetetraacetic-acid (EDTA), acid-citrate-dextrose (ACD), lithium heparin (LH) and serum separator tubes (SST)) and stored at 4◦C or room-temperature for 0, 1, 2, 3, 4, 5 and 6 days before processing. Multiplex serology was used to determine antibody reactivity against 35 antigens derived from human papillomaviruses, human polyomaviruses, Epstein Barr Virus and Helicobacter pylori. Cohen's Kappa statistic was used to measure agreement on seropositivity status between samples exposed to standard and non-standard clinical practice conditions. Results: For samples processed without delay, Kappa was not associated with storage-temperature (p-value range 0.23 to 0.95) or vacutainer-type (p-value range 0.35 to 0.89). Kappa did not significantly decline with increasing delays in processing for any vacutainer-type storage-temperature combination (p-slope range 0.06 to 1.00). Conclusions: Antibodies to epitopes from various pathogenic infectious agents can be measured reliably from samples stored in SST, EDTA, ACD or LH vacutainers at either room-temperature or 4◦C for up to six days before processing. Impact: Serological testing is robust to several pre-analytical options. These findings are particularly important for epidemiological studies recruiting participants from remote settings where sample exposure to pre-analytic conditions can vary considerably.The Cancer Council NSW Stability Study is funded by Cancer Council NSW