Preparing a Cell Block

There are several methods that can be used to prepare a cell block. The method chosen is dependent upon the characteristics of the specimen. Most labs have multiple cell block methods in their repertoire, and make the choice depending on the characteristics of the specimen.

If a cytology specimen contains small fragments of tissue, they should be carefully picked out and submitted as a cell block. Similarly, clots or heavy mucus can be used.

Loose cells are difficult to contain, embed, and section; and therefore make poor cell blocks. A method should be employed with all loose cellular material to 'block' it together so that it can be handled 'en mass'. There are several methods for doing this including the use of plasma-thrombin, albumin or agar.


Figure 1: Loose cells placed in lens paper make a poor block, and most do not survive processing. Often there is no visible material to embed into paraffin.