In their excellent review on plasma apolipoproteins, Rader and colleagues [1] recommend that fasting determinations of both apolipoprotein B (apo B) and lipoprotein(a) (Lp[a]) levels should be made in persons with coronary artery disease who are not candidates for pharmacologic therapy as determined by low-density lipoprotein (LDL) cholesterol levels less than 3.4 mmol/L (130 mg/dL). Within this group, the patients with elevated levels of apo B, Lp(a), or both are considered candidates for drug therapy. However, in the authors' algorithm, the patients with normal levels of apo B and Lp(a) and low levels of high-density lipoprotein (HDL) cholesterol are still considered candidates for drug therapy. This algorithm should first recommend a determination of HDL cholesterol levels in patients with coronary artery disease and LDL cholesterol levels less than 3.4 mmol/L (130 mg/dL). According to the authors' algorithm, those with low HDL cholesterol levels would be considered candidates for drug therapy, regardless of their levels of apo B or Lp(a). In the patients with normal HDL cholesterol levels, the determination of apo B and Lp(a) levels would then identify those for whom drug therapy would be recommended.

The same consideration can be applied to Rader and colleagues' algorithm for persons with a family history of premature coronary artery disease and LDL cholesterol levels between 3.4 and 4.9 mmol/L (130 to 190 mg/dL). Those with low HDL cholesterol levels would be considered for drug therapy regardless of their levels of apo B and Lp(a); determinations of apo B and Lp(a) would only be recommended for persons with normal HDL cholesterol levels.

These changes to the authors' algorithms will significantly reduce the cost of diagnostic laboratory tests without sacrificing the quality of the decision-making process.