ABO grouping of highly-dilute blood by the absorption-elution technique using nitrocellulose beads--application to a casework investigation.

This paper reports a homicidal case in which the absorption-elution technique using nitrocellulose beads as immunoadsorbents was successfully applied to ABO grouping from highly-diluted blood. A 21-year-old man was found dead in bed while staying in a hotel. He had multiple wounds over the entire body. By autopsy the cause of death was decided to be traumatic shock. The victim's blood group was A. A bucket filled with faint-colored water was found at the scene. By means of the absorption-elution technique using nitrocellulose beads the water was grouped as B. Later, a 32-year-old man staying in the hotel together with the victim was suspected and arrested. The suspect's blood group was B. He confessed that he had injured himself in the hands with a knife during the struggle and washed them in the water.