Standardization in biological staining. The influence of dye manufacturing

The purpose of biological staining is to obtain specimens of biological material that can be assessed in the microscope. These specimens are influenced by all processes from removal from the intact organism to mounting on the microscopic slide. To achieve comparable results with various techniques for biological staining, standardization of all procedures and reagents is mandatory. In this paper, I focus particularly on dyes and consider the possibilities for obtaining standardized dyes. In general practice, most biological staining takes place with available commercial dyes. These dyes may or may not have been subjected to quality assessment either internally by the producer or vendor or externally by independent investigators or organizations such as the Biological Stain Commission. Concerted attempts at standardization in Europe are discussed. The latest results of this work, the European standard EN 12376, is presented. This standard is concerned with information supplied by the manufacturer with in vitro diagnostic reagents for biological staining. The standard has been prepared by a Working Group on Staining in Biology under Technical Committee 140, In Vitro Medical Devices, of the European committee for standardization, CEN.