Salivary Total Protein as a Forensic Identification Tool: A Preliminary Exploratory Study

The personal identification of unknown individuals continues to pose a significant challenge in the aftermath of criminal activities and mass disasters. Saliva is among the most frequently encountered biological fluids, as the oral cavity readily comes into contact with various surfaces, making it a valuable source of forensic evidence. The present study aimed to assess sex differences and age-related variations in total salivary protein levels. This in vivo prospective study included a total of 120 participants. Approximately 5 mL of whole unstimulated saliva was collected from each subject and subsequently centrifuged at −20°C. The resulting supernatant was carefully aspirated, and the aliquots were stored at −20°C until the biochemical assay was performed. The salivary protein quantification was done by the Bradford assay. Statistical analysis was done using Stata version 17. A highly significant statistically difference in protein concentration was seen between age groups ( p < .0001), with lower values reported in the geriatric population. A highly statistically significant difference in protein concentration was seen between males and females ( p < .0001), with higher values reported in females. A statistically significant difference in protein concentration was seen among age groups ( p = .026), with lower values reported in the post-dental eruption group. The total salivary protein concentration can predict gender with a specificity of 23% and a sensitivity of 65%. It can be predicted whether an individual would belong to the geriatric population or other age groups with a specificity of 83% and a sensitivity of 73%. This shows that salivary total protein has limited predictive strength and can be used as an adjunct to the existing forensic identification methods.