The standard mouse assay of anti-venom quality does not measure antibodies neutralising the haemorrhagic activity of Vipera ammodytes venom

► Vipera ammodytes (Va) envenomation causes primarily haemorrhagic and rarely neurotoxic pathologies. ► Haemorrhage is due to haemorrhagins (H) and neurotoxicity to neurotoxins (Atx) from Va venom. ► Functional antibodies against H (anti-H) and neurotoxins (anti-Atx) from Va venom were prepared. ► Anti-Atx participated in neutralisation of the whole venom toxicity in mice, while anti-H were not protective. ► Anti-H, that neutralise haemorrhages, are not measured by regulatory antivenom potency assay.