There has been some uncertainty in the past arise in cases where a couple have been civilly married in a State which does not require a serological [blood] test. In all cases where a couple has been legally married in any State or Country of the world, they are entitled to go to any temple of the Church if properly recommended by their bishops and stake presidents, or branch and mission presidents, and are otherwise worthy to be sealed for time and eternity, without complying with the laws of the State or Country in which the temple is located. We give full recognition to the married status of such couples created under the laws of the land in which they were civilly married. It is this legal marital status which gives us the right to perform our temple sealings without compliance with the provisions of the laws which apply to the creation of the marital status by the civil law. Therefore, if a couple are legally married in a State or Country in which no serological test is required, they are not obligated to undergo such a test in the State or County in which the temple is located as a condition precedent to their participating in the sealing ordinances of the temple.
[David O. McKay, J. Reuben Clark Jr., and Henry D. Moyle, circular letter, May 31, 1961, quoted in Anderson, Devery; The Development of LDS Temple Worship, 1846-2000: A Documentary History, http://amzn.to/TempleWorship]