Advanced acid-base interpretation builds on the four basic disorders (respiratory acidosis, respiratory alkalosis, metabolic acidosis, metabolic alkalosis) to recognize more complex clinical realities: mixed acid-base disorders, the clinical significance of the anion gap, the delta-delta calculation that uncovers triple disorders, expected compensation ranges, and high-yield clinical scenarios such as diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic state (HHS), septic lactic acidosis, and toxic ingestions. For the NCLEX-RN, this level of analysis appears in complex, multi-system patient scenarios and ICU-level presentations. You will not be asked to derive Winter's formula by hand, but you must reason through what an arterial blood gas (ABG) is telling you, decide which disturbance threatens the patient most urgently, and select the nursing priority that follows. The ability to correctly identify and prioritize acid-base findings drives correct, safe nursing interventions and timely escalation. The normal reference ranges anchor every interpretation: pH 7.35-7.45, PaCO2 35-45 mmHg, HCO3 22-26 mEq/L. A pH below 7.35 is acidemia; above 7.45 is alkalemia. The body never overcompensates back to a normal pH, so a truly normal pH in the setting of grossly abnormal...