Red Flags and Decision Making in Laboratory Medicine is a forensic guide to errors, ethics, and irreversible decisions in modern laboratories, showing how technically correct results fail when judgment, documentation, and defensibility are weak. It examines real cases where routine habits, silent assumptions, mislabeled samples, calibration drift, fatigue, and documentation gaps quietly destroy credibility. The book explains why audit trails and accountability often matter more than analytical precision, and how missed warning signs lead to legal, ethical, and professional consequences. Covering risks from sample collection to reporting and beyond, it reminds readers that every result is a chain of decisions, not just data. Written for pathologists, laboratory leaders, technologists, analysts, and postgraduate students, it serves anyone whose signature carries responsibility, emphasizing that in today’s digital laboratories, the most dangerous errors are unexamined decisions, because truth fails quietly and then permanently.