Medico-Legal Application of Blood Groups
Forensic Serology & Genetics: Personal Identification
1. Primary Medico-Legal Uses
While DNA profiling has largely superseded conventional blood grouping for identification, ABO and Rh blood groups remain relevant in specific contexts:
- Disputed Paternity: Historically the gold standard. It serves as an exclusionary test—if the child’s blood group is incompatible with the alleged father, paternity is excluded.
- Criminal Investigations: Linking a suspect to a crime scene (e.g., blood stains found on a suspect’s clothing matching the victim).
- Personal Identification: Assisting in the identification of deceased individuals, especially in mass disaster scenarios.
2. Key Forensic Concepts
| Term | Forensic Application |
|---|---|
| Secretors | Individuals who secrete ABO blood group antigens in body fluids (saliva, semen, vaginal fluid). Essential for forensic analysis of non-blood evidence. |
| Lattes Crust Test | A laboratory method used to determine the ABO group of dried blood stains. |
3. Forensic High-Yield Pearls
- Exclusionary Power: Blood grouping is excellent for excluding an innocent suspect, but its power of inclusion is low due to the high frequency of blood types in the general population.
- DNA Advantage: DNA profiling (STR analysis) provides near-universal individual identification, making blood grouping a supplementary rather than a primary tool in modern forensic science.
- Educational Resource: For comprehensive serology protocols, genetics case studies, and medical practice questions, visit mymedschool.org.