Evolution of Pap Stain

Abstract

Pap stain was first developed by Dr GN Papanicoloau in 1947 and since then it has been used successfully to screen cervical cancer. In fact, it has reduced the incidence of cervical cancer by 70% especially in developed countries having well planned screening programs. However, the stain has undergone various modifications from regressive conventional method to progressive rapid Pap staining where the time taken for staining was reduced. Further the stain was modified as ultrafast Papanocoloau stain and modified ultrafast Pap stain were air dried cervical smears were used and staining time was reduced. Later the other modifications were Enviro- Pap stain which was environmentally friendly with results similar to conventional method; REAP stain which was rapid and economical and Cytocolor developed by Merck where isopropyl alcohol is replaced by Propanol. Each method has advantages and disadvantages. Hence laboratories should develop their own protocol and standardize the staining technique.