Who can participate in the Lord's Supper?

The Lord's Supper is biblical and I believe that all people who are partakers of Christ's body should be involved, because when you eat bread and drink the wine you're saying is part of the Lord's table (if you truly believe in their salvation ). But most denominations have made a meal of the liturgy and bureaucracy where it is prohibited the participation of people who are truly of Christ, two examples are nondenominational Christians (like me) and the disciplined within the church.
The unnamed are barred from the supper because they are regarded as non-Christian, because to evangelicals, evangelicals are not all that are ungodly, the Apostle Paul says that each one examine himself and eat and drink, does not no mention "itself is a member of any evangelical church and is in communion with his church" (not have it in the Bible).
The disciplined the issue is more serious, disciplined brothers are all members of a church that has committed sin and was discovered by the leadership, and thus cut was the right to participate in some liturgies of the church, including part of the meal, making Brother disciplined worse than Judas betrayed Jesus, that Jesus knew who Judas was, nor why it did not take Judas left the supper. The supper should be free to decide themselves what each one is or is not of Christ, each one examine himself.

Rogerio Oliveira.