In the article entitled "Determination of Coumarin-type Anticoagulantsin Human Plasma by HPLC-Electrospray Ionization Tandem MassSpectrometry with an Ion Trap Detector" by M. Kollroser andC. Schober
(Clin Chem 2002;48:8491), the phrase "phenylpropylring" in line 2 of the second column on page 90 should read"phenyl ring". In addition, the proposed product ion structuresin Fig. 2
were incorrectly drawn. The correct structures areshown below. The authors thank Douwe de Boer for pointing outthese errors.