transfusion-related decisions in the perioperative setting are often complex due to acute variations in the hemoglobin levels, which typically experience a progressive decrease within days. This process, commonly referred to as "hemoglobin drop" or "hemoglobin drift", has been observed to be highly variable among patients and reliant on several variables, such as the volemic status, fluid balance and blood loss. Although it has been investigated and some predictors have been identified, postoperative hemoglobin drop remains unpredictable and is not fully clarified. In consequence, hemoglobin levels' variations are frequently misunderstood, hindering the decision to transfuse.

Inclusion Criteria:

• Adult patients electively scheduled for laparoscopic urologic and gynecologic surgery.

Exclusion Criteria:

• Suspected or confirmed coagulopathy (including current treatment with anticoagulants or antiplatelet agents).
• Requirement for surgical gauzes during surgery, including conversion to open surgical techniques.
• Transfusion of red blood cells (RBCs) or use of blood recovery systems during the perioperative period.
• Significant postoperative bleeding (> 50 ml in surgical drains, gross hematuria, or any other type of significant blood loss).
• Postoperative hemodynamic instability (defined as requirement of vasoactive drugs).
• Other major postoperative complications during the observable period.

Adult patients electively scheduled for laparoscopic urologic and gynecologic surgery.