The preoperative laboratory screening is commonplace in clinical practice and is traditionally defined as the practice of prescribing laboratory testing before surgery on patients undergoing a given procedure. The wide heterogeneity of the solutions prospected over the past decades emphasizes the objective difficulty at issuing definitive guidelines and recommendations. Despite its widespread use, a systematic evaluation of the clinical and cost-effectiveness of routine laboratory testing demonstrates that several approaches are as yet unsuitable, as inappropriate investigations may lead to evaluation of borderline or false-positive laboratory abnormalities. Three major difficulties can be identified when issuing reliable recommendations: articulation and appropriateness of diagnostic protocols, contestualization, in terms of surgical procedures and suitable clinical contests that might achieve the greatest advantages from results of laboratory testing, and impact of these tests on clinical management and outcome. This article aims to provide a comprehensive review of the current literature on this topic, attempting to suggest a suitable approach to the puzzling issue of preoperative laboratory testing.