Lugol's test reexamined again: buccal cells.

Area of Science:

• Forensic science
• Oral cytology

Background:

• Glycogen detection in oral epithelial cells is crucial for forensic analysis.
• Water extraction significantly impacts glycogen levels in buccal cells.

Purpose of the Study:

• To investigate the effect of water extraction on glycogen levels in oral epithelial cells.
• To establish a threshold for identifying oral samples in forensic contexts.

Main Methods:

• Lugol's iodine staining technique was applied to oral samples.
• Saliva and buccal epithelial cells were examined before and after water extraction.
• Analysis included samples from individuals and sexual assault kits.

Main Results:

• Water extraction drastically reduced glycogen-positive buccal cells from 49/3,951 to 0/4,000.
• Less than 1% of epithelial cells were glycogen-positive after water extraction in all tested samples.
• 119 saliva samples from sexual assault kits showed less than 1% glycogen-positive cells.

Conclusions:

• A threshold of >1% glycogen-positive nucleated squamous epithelial cells after water extraction suggests a non-oral source.
• This finding aids in the forensic elimination of the mouth as the origin of biological samples.
• Refined criteria for oral fluid analysis in forensic investigations.