Comparison of total serum lipids measured by two methods

To accurately assess vitamin E status, the ratio of serum vitamin E to total serum lipids is required. We compared two methods of measuring total serum lipids: (a) the calculated sum of measured cholesterol, triglycerides, and phospholipids, and (b) the colorimetric method. Over the entire range of total lipid concentrations (151-1,728 mg/dl), there was an excellent correlation between methods (r = 0.930; p less than 0.001). No significant differences between measurements by these methods were found over the entire range and between 0 and 1,000 mg/dl; however, between 1,000 and 1,728 mg/dl, the measured total lipid concentration was higher (p = 0.023) than the added total lipid measurements. Despite this discrepancy, the methods appear comparable for clinical use in assessing vitamin E/total lipid status; the measured total lipids would be the preferred method because of the low cost and ease of performance of the test.