TRICHROME STAIN: Procedure Notes

1. The single most important step in the preparation of a well-stained fecal smear is good fixation. If this has not been done, the protozoa may be distorted or shrunk, may not be stained, or may exhibit an overall pink or red color with poor internal morphology.

2. Slides should always be drained between solutions. Touch the end of the slide to a paper towel for 2 s, to remove excess fluid, before proceeding to the next step.

3. Incomplete removal of mercuric chloride (Schaudinn's fixative and PVA) may cause the smear to contain highly refractive crystals or granules which may prevent finding or identifying any organisms present. Since the 70% ethanol-iodine solution removes the mercury complex, it should be changed at least weekly to maintain the strong tea color. A few minutes is usually sufficient to keep the slides in the