It is well known that accurate assessment of serum alpha-tocopherol requires knowledge of the serum lipids also present. Patient specimens (n = 307) within the standard reference limit of 5-18 mg/L were used to determine the following 95 percent reference interval for a lipid ratio of alpha-tocopherol to the sum of cholesterol and triglycerides [E/(C + T)]: 1.4 (1.20-1.56) - 5.7 (5.51-6.91) mg/g (90 percent confidence interval). In terms of alpha-tocopherol status, patients with low results (< 5 mg/L) were normal on reevaluation with the lipid ratio in 47 percent of those examined (28 of 59), and elevated results (> 18 mg/L) were normal or low in 58 percent (26 of 4.5). Elevated triglycerides developed from non-fasting specimens were one common reason for misleading results when lipids were not considered. When measuring alpha-tocopherol in a patient population, evaluation of the lipid content is needed for accurate assessment in a significant number of cases.