DIRECT WET SMEAR: Introduction (cont.)

placed at the edge of the coverslip or a new wet mount can be prepared with iodine alone. A weak iodine solution is recommended; too strong a solution may obscure the organisms. The color should resemble "strong tea." Several types of iodine are available; D'Antoni's will be discussed here. Gram's iodine used in bacterial work is not recommended for staining parasitic organisms.

If preserved specimens are submitted to the laboratory, it will be more cost-effective and clinically relevant to delete the direct smear and begin the stool examination with the concentration procedure, particularly since motile protozoa will not be viable because of the prior addition of preservative. With few exceptions, intestinal protozoa should never be identified on the basis of a wet mount alone; permanent stained smears should be examined to confirm the specific identification of suspected organisms.