For the universal church and in the guidelines offered by different bishops’ conferences distinctions are made between the faithful of the Orthodox churches and the faithful of the Anglican and mainline Protestant churches.
The Catholic Church recognizes the validity of Orthodox sacraments and welcomes members of the Orthodox churches to receive the sacraments in a Catholic Church, although it cautions that their Orthodox pastors and bishops might object.
The U.S. bishops’ brief guidelines, published in 1996, said, “Members of the Orthodox churches, the Assyrian Church of the East and the Polish National Catholic Church are urged to respect the discipline of their own churches. According to Roman Catholic discipline, the Code of Canon Law does not object to the reception of Communion by Christians of these churches.”
For Anglicans and Protestants, the situation is more complicated and Catholic church law requires that they “manifest Catholic faith in this sacrament,” as the directory phrased it.
Shared faith in the real presence of Christ in the Eucharist is not unlikely, however, because it formally has been affirmed over the course of more than 50 years of formal theological dialogue between the Catholic Church and the Anglican and mainline Protestant churches.
Therefore, the norms published by the Diocese of Rockville Centre, New York, in 1999 stated, “Episcopalians and Lutherans can be presumed to believe in the real presence. For members of other communions there may be need for some further discussion concerning their belief in the Eucharist.”