Evaluation of lactophenol cotton blue stain for detection of eggs of Enterobius vermicularis in perianal surface samples.

A lacto-phenol cotton blue (LPCB) stain for detecting eggs of Enterobius vermicularis in perianal surface samples was evaluated prospectively. Two hundred children treated in the paediatrics ward and outpatients department of Jipmer Hospital in Pondicherry were studied. From each child two anal surface samples were collected by Scotch cellophane tape method. One cellophane tape containing anal surface samples was pressed against surface of the glass slide containing a drop of LPCB while another cellophane tape was placed on a clean glass slide without adding any LPCB. Both the specimens from each child were examined by microscopy for presence of the eggs of the parasite. The anal samples collected from 50 children were positive for the eggs of E. vermicularis--48 were detected by cellophane tape using LPCB and 36 by cellophane tape method without using any LPCB. Using LPCB stain, naturally transparent and colourless eggs of the parasites were stained deep blue which facilitated their easy detection and accurate identification in routine microscopy. We therefore recommend Scotch cellophane tape using LPCB as a simple, rapid, inexpensive and overall more sensitive method for detecting E. vermicularis eggs in anal surface samples for diagnosis of enterobiasis in children.