Quality control and validity check of the solid-phase spectrophotometric procedure (Me-SPS) for determination of heavy metals important in pharmaceutical practice: zinc (Zn-SPS), lead (Pb-SPS), and cobalt (Co-SPS) were performed using a very simple and informative prevalidation concept. Further, metrological characteristics of the Me-SPS procedure together with the diagnosis of particular prevalidation steps were evaluated. Favourable prevalidation characteristics, i.e., ideal analytical function, homogeneity of data material, low limit of quantitation, and acceptable accuracy verified the quality of the Me-SPS procedure and pointed to the limitations of some investigated systems.