IRON HEMATOXYLIN STAIN: Limitations

1. The permanent stained smear is not recommended for staining helminth eggs or larvae; they are often too dark (excess stain retention) or distorted. However, occasionally they may be recognized and identified. The wet smear preparation from the concentrate is the recommended approach for identification of helminth eggs and larvae.

2. The smear should be examined with the oil immersion lens (100 x) for the identification of protozoa, human cells, Charcot-Leyden crystals, yeast cells, and artifact material. Quantitation of these cells and other structures is normally done from the examination of the permanent stained smear, not the wet smear preparations (direct wet smear, concentration wet smear).

3. This high-magnification (oil immersion; total magnification of x 1,000) examination is recommended for protozoa, particularly for confirming species identification.