Hypocalcemia is also an important electrolyte disturbance in critically ill dogs and cats. The incidence of hypocalcemia is 16% in critically ill dogs and 24% in dogs with sepsis. Hypocalcemia is best detected by measuring ionized calcium (<2.5 mEq/L), which is the biologically active form, rather than total or corrected calcium. Hypocalcemia, hypovitaminosis D, and metabolic acidosis occur in dogs with induced endotoxemia. LPS may mediate a decrease in vitamin D–binding protein, with subsequent loss of vitamin D in the urine. Also, dogs with blunt and penetrating traumatic injuries, particularly abdominal trauma, are significantly more likely to have ionized hypocalcemia (16% incidence). These dogs spend longer time in the hospital and ICU, require more intensive therapies, and are less likely to survive (57% survival rate) than dogs with normocalcemia (89% survival rate). Hypocalcemia from critical illness or traumatic injury can cause clinical signs similar to those of puerperal hypocalcemia (hyperexcitability, including tremors, twitching, spasms, or seizures, or more subtle signs related to cardiovascular collapse).