A specific chromatographic LC/MS/MS assay is described for the confirmatory identification of residues of sarafloxacin, an arylfluoroquinolone antibacterial agent, in catfish tissue. This confirmatory method takes advantage of the specificity provided by sample preparation, liquid chromatography, and tandem mass spectrometry. This kind of multidimensional analysis is commonly used in environmental, pharmacokinetic, residue, and other studies. However, we demonstrate the addition of a previously unreported criterion, the use of ion ratio ranges from the tandem mass spectrometry (MS/MS) experiment as an aid in confirmation. Using the described method, we were able to achieve MS/MS product ion ratios with <7% variation during 1 day of analysis for over 25 injections. We believe the addition of this criterion will increase the scientific certainty of the confirmatory method.