# Detection of ABO Blood Groups From Dentin and Pulp by Using the Absorption-Elution Technique: A Forensic Cross-Sectional Study Among the Population of the Al Jouf Province, Saudi Arabia

## TL;DR

This study shows that ABO blood groups can be reliably detected from tooth pulp and dentin using the absorption-elution technique, which is useful in forensic identification.

## Contribution

The study validates the use of both pulp and dentin for ABO blood group detection in a forensic context, with no significant differences based on age or gender.

## Key findings

- Both pulp and dentin showed positive ABO and Rh factor antigens with no significant difference in performance.
- Pulp showed marginally higher accuracy compared to dentin in blood group identification.
- No correlation was found between blood group detection and age or gender in the 45 samples analyzed.

## Abstract

Background and objective

Human teeth have a significant forensic importance. As they are the hardest of all human tissues, they are not just chemically stable but also their characteristics are maintained for a long time after death even in the most harsh environmental conditions. Despite the advances made in DNA analysis, fingerprinting, etc., ABO blood grouping still plays a significant role in the forensic practice in the field of personal identification, paternity disputes, and several other scenarios including the identification of mass disaster victims. The term blood groups refers to inherited antigens on the surface of red blood cells (RBCs) detected by specific antibodies. Since tooth pulp contains numerous blood vessels, blood group antigens are most certainly bound to be present in tooth pulp. Various studies have shown that blood group antigens in the pulp and dentin are preserved as long as up to two years after the demise of an individual. Absorption-elution technique has been proven to be the most sensitive, reliable, and consistent method to determine the ABO blood group from both the pulp and dentine. This study aimed to ascertain the ABO blood group from both the hard (dentin) as well as the soft tissue (pulp) of the tooth by using the absorption-elution (AE) technique and also to determine if there are any variations in identifying the blood groups from the teeth based on age and gender.

Material and methods

After obtaining due consent, we included patients of both genders aged between 16-60 years visiting the outpatient department (OPD) clinics at the College of Dentistry for periodontal or orthodontic extractions. One patient's blood type was determined by using the slide agglutination technique before any capillary blood extraction was performed; this patient served as a control. For this investigation, we used the pulp and powdered dentin samples taken from the dental extractions to test for the presence of ABO and Rhesus (Rh) factor antigens by using the AE method. The study samples were compared with the control for blood group determination. Statistical analysis was carried out using the chi-square test with Monte Carlo (MC) simulation to check for any correlation of blood grouping with age and gender.

Results

The dentin and pulp were shown to have positive blood group antigens for the ABO and Rh factors. While neither pulp nor dentin performed significantly differently in identifying the blood group antigens, pulp showed marginally higher accuracy. There was no discernible difference regarding gender or age in the dentin or pulp of any of the 45 samples studied.

Conclusions

For determining an individual's blood type and Rh factor, both the hard (dentin) and soft (pulp) tissues of a tooth are valid sources. This is particularly helpful in forensic medicine cases where teeth are the only remains that can be viably used to find out a person's identity.