Estimated Blood Loss: Novel Model for Estimating Surgical Blood Loss.

Inclusion Criteria: * Patients scheduled for elective urologic laparoscopy surgery. Exclusion Criteria: * Patient with suspected or confirmed heart failure, severe hypertension, hepatic cirrhosis, chronic kidney disease on dialysis, coagulopathy, as well as patient receiving diuretics, anticoagulant or antiplatelet agents. * Cases in which surgical gauzes were used, including conversion to open surgical technique. - Patients who have received transfusions of RBCs during the perioperative period. * Patients who have showed postoperative bleeding, defined by an amount greater than 50 ml in surgical drains, or any other type of blood loss.