Uniform Determination of Death Act
The National Conference of Commissioners on Uniform State Laws produced the Uniform Determination of Death Act, which has been adopted in 45 states and recognized in the rest through judicial opinion 1).
1)
National Conference of Commissioners on Uniform State Laws. Uniform Determination of Death Act, 1981 (http://www.uniformlaws.org/shared/docs/determination%20of%20death/udda80.pdf).