The publication of the West of Scotland Coronary primary prevention (WOSCP) trial of pravastatin (a cholesterol lowering drug) created a stir. It is now used to justify the testing and treating of asymptomatic individuals at risk of coronary artery disease. However, two issues need careful attention: first, the generalizability of the study, and, second, the issue how to identify individuals likely to benefit from treatment. The purpose of this paper is: (1) to conduct an appraisal of the WOSCP trial, and (2) to review the effectiveness evidence on cholesterol testing; more specifically, to evaluate the ability of lipid tests to correctly identify individuals at risk of coronary heart disease. The WOS trial is appraised using established methodological criteria. The appraisal shows that (1) the WOS trial was conducted in a population with the highest worldwide risk of coronary heart disease, (2) from this population, middle-aged men with very high cholesterol levels were selected, (3) 16% of the men included had established coronary heart disease. In this group, after five years, the size of the treatment effect ranged from 0.7% for cardiovascular mortality to 3.7% for non-fatal MI or CHD deaths combined. Furthermore, the review of the ability of lipid test to correctly identify individuals at risk of coronary heart disease revealed that these tests are very poor at distinguishing between people at risk or not at risk of coronary artery disease. This paper concludes that (1) the generalizability of the West of Scotland trial needs careful examination, and (2) even if the trial is generalizable, the question of how to identify individuals likely to benefit from treatment, remains to be answered.