wetfixed

Wetfixed is a term used in histology, cytology, and related biological fields to describe specimens preserved by immersion in liquid fixatives rather than by air-drying or freezing. The goal of wet fixation is to halt enzymatic processes and preserve cellular and tissue architecture for subsequent analysis.

In practice, wet fixation involves placing tissue samples or prepared slides in a fixative solution for a defined period, at room temperature or under refrigerated conditions. Formaldehyde-based fixatives, such as formalin or paraformaldehyde, are among the most common for light microscopy, while glutaraldehyde is used for electron microscopy. Alcohol-based fixatives (ethanol or methanol) are also widely used, especially for cytology and certain immunohistochemical applications. After fixation, specimens may be processed through dehydration, clearing, and embedding for histology, or prepared as stained slides when used as wet mounts.

Advantages of wet fixation include reliable preservation of morphology and broad compatibility with staining and diagnostic workflows. Limitations include exposure to hazardous chemicals and potential crosslinking of proteins that can mask antigenic sites or affect nucleic acid integrity; fixation duration and temperature must be carefully controlled to avoid artifacts.

In cytology, wet-fixed smears refer to slides fixed immediately in fixative to preserve delicate cellular details prior to staining. Overall, wet fixation remains a standard approach in tissue preservation, balancing preservation quality with downstream analytical compatibility.