A. Potentially lethal	High potential for life‐threatening adverse reactions Potentially lifesaving drug at a dosage too low for the disease being treated High dosage (>10 times normal) of drug with low therapeutic index
B. ‐ Serious	Route of administration could lead to severe toxicity low dosage of drug for serious disease in patient with acute distress High dosage (4‐10 times normal) of drug with low therapeutic index Dosage resulted in serum drug concentration in potentially toxic range Drug could exacerbate the patient's condition (related to warnings or contraindications) Misspelling or mix‐up in medication order could lead to dispensing of wrong drug Documented allergy to drug High dosage (10 times normal) of drug without low therapeutic index Omission of pretest for drug hypersensitivity
C. Significant	High dosage (1.5‐4 times normal) of drug with low therapeutic index Drug dosage too low for patient's condition High dosage (1.5‐10 times normal) of drug without low therapeutic index Errant dual‐drug therapy for single condition Inappropriate dosage interval omission from medication order
D. Minor	Incomplete information in medication order Unavailable or inappropriate dosage form Nonformulary drug Noncompliance with standard formulations and hospital policies Illegible, ambiguous, or nonstandard abbreviation
E. No error	Information or clarification requested by physician or other health care professional from pharmacist Cost savings only