A general purpose reagent is a chemical reagent that has general laboratory application, that is used to collect, prepare, and examine specimens from the human body for diagnostic histopathology, cytology, and hematology, and that is not labeled or otherwise intended for a specific diagnostic application. General purpose reagents include cytological preservatives, decalcifying reagents, fixatives and adhesives, tissue processing reagents, isotonic solutions, and pH buffers.

A solution composed of iodine and potassium iodide, which can be used as a reagent and antiseptic, with potential use in cancer diagnosis. The iodine in Lugol's solution selectively binds to alpha-1,4 glucans found in polysaccharides, such as glycogen. Lugol's solution reacts with glycogen in normal, healthy non-keratinized, squamous epithelium and the iodine-glucan complex stains the glycogen-containing cells dark brown. Cancer cells are devoid of glycogen, so these cells will stay unstained. The presence of cancer cells can be detected by the degree of staining and the neoplastic cells can be surgically removed. High-grade intraepitheial neoplasia has almost no glycogen-containing epithelium.

Lugol's solution, antiseptic introduced into medicine in 1829 by the French physician Jean Lugol. An effective bactericide and fungicide, Lugol's solution is a transparent brown liquid prepared by dissolving, first, 10 parts of potassium iodide, then 5 parts of iodine, in 85 parts of water. It is...