Abstract
The analytical and biological components of variation of total cholesterol, high density lipoprotein (HDL) cholesterol, HDL3 cholesterol, HDL2 cholesterol and apolipoproteins A-I and B in serum were assessed in 12 apparently healthy individuals. All analytes showed marked individuality and therefore conventional population based reference intervals are of little use. The differences required for serial results to have changed significantly for these assays were calculated. The data presented confirm that the assays studied have limited value in screening the general population.