I don’t think Seventh Day Adventists are apostate. They acknowledge the Trinity and believe Jesus is God. Their views on eschatology and soul sleep are, in my opinion, a bit heterodox but certainly not vital to saving faith.
I'm not SDA. I study, write, pray, work, and teach, frequently and as the Lord directs. Pretty idyllic really. You could call me a Messianic Jew (25% by blood) except for the fact that I wasn't raised Jewish. I really don't think such things are that all fired material.
Oh and do check out that link. You might learn something of value.