Shedding more light on shedders

Area of Science:

• Forensic science
• Human biology
• Biometrics

Background:

• Previous research on 11 donors suggested a continuum of shedder types.
• Reproducibility of cell staining for shedder status assessment in large populations was undetermined.

Purpose of the Study:

• To assess the reproducibility of cell staining for determining shedder status in 100 individuals.
• To investigate potential differences in cell deposition between sexes and hands.
• To analyze cell deposition over time post-handwashing.

Main Methods:

• 100 individuals tested for shedder status using DNA binding dye on thumbprints.
• Cell counts (cells/mm²) recorded at 220x magnification.
• Samples collected from both thumbs at multiple time points (0-180 min) post-handwashing, in triplicate, over three days.

Main Results:

• 98 out of 100 donors exhibited reproducible cell deposition.
• No significant difference in cell deposition between left and right thumbs in most cases.
• Males tended to deposit more cells than females.
• Many donors fell into intermediate categories when applying arbitrary boundaries for shedder status.

Conclusions:

• Human skin cell deposition is a reproducible phenomenon suitable for large-scale testing.
• Shedder status is best described as a continuum rather than discrete categories.
• Further research may refine shedder status determination and its forensic applications.