Registered nurses must interpret complex laboratory panels and integrate findings into clinical decision-making. Arterial blood gas (ABG) analysis evaluates acid-base balance through measurement of pH, PaCO2, HCO3, and PaO2, enabling identification of respiratory or metabolic disturbances and their compensation status. Cardiac biomarkers such as troponin and BNP provide time-sensitive data critical for differentiating acute coronary syndromes from heart failure. Comprehensive coagulation studies guide anticoagulant therapy monitoring, while liver function tests reveal hepatocellular injury, cholestasis, and synthetic function through patterns of enzyme elevation.