The checkerboard tissue block. An improved multitissue control block.

We describe an improved method of embedding a large number of tissue samples in a single, normal-sized paraffin block. Because the tissues are evenly distributed in a checkerboard arrangement, they can be readily identified by their position in the resulting sections. This device permits rapid and inexpensive screening of new histologic reagents, and facilitates intra- and interlaboratory quality control.