In a dehydration sequence, what is the first step for a 4mm specimen?

In the dehydration sequence during tissue processing for histopathology, the initial step is often to immerse the specimen in a lower concentration of ethanol, typically around 70% ethanol. This step is crucial because it gradually removes water from the tissue while helping to maintain the structural integrity of the cellular components.

Using a 70% ethanol solution allows for the initial extraction of free water in a controlled manner, reducing the risk of damaging delicate tissue structures that could occur with higher concentrations of alcohol. This gentle introduction to the dehydration process is particularly important for specimens of a size like 4mm, as it ensures careful handling of the tissue.

Once the initial dehydration with 70% ethanol is completed, the specimen would then progress to higher concentrations of ethanol, ultimately reaching 100% ethanol for more thorough dehydration. This stepwise approach minimizes artifacts and preserves the morphological characteristics necessary for accurate histological evaluation.