Reducing Post-bleeding Mortality Of

Biomedical companies extract blood from the horseshoe crab, Limulus polyphemus, for the production of Limulus Amebocyte Lysate, used worldwide for detecting endotoxins in injectable solutions and medical devices. Despite the extensive use of horseshoe crabs by the biomedical industry, total hemolymph volume in animals of a given size is not known. The hemolymph volume of 60 adult horseshoe crabs was determined using an inulin dilution technique. Blood volume of the horseshoe crab represented as a percentage of wet body weight was 25 ± 2.2% for males and 25 ± 5.1% (mean ± S.D.) for females. A linear relationship of hemolymph volume to weight (P = 0.0026, r = 0.8762), an exponential relationship between hemolymph volume and prosomal width (P < 0.0001), and an exponential relationship between hemolymph volume and inter-ocular width (P < 0.0001) were observed. No significant differences were observed between males and females. The relationship of horseshoe crab size and hemolymph volume can be used to predict how much blood can be drawn from the animals used by the biomedical industry, and to predict any resulting bleeding mortality.