Identify If A Given Feed Has Specific Optional Tags?

I'm back to doing simple coding with VS 2010 (beta) after many years away (going back to VB3 with most of my coding going back to QB and VB-DOS) so it's all pretty cryptic right now.

I'm using XPATH to traverse RSS feeds and I need a way to identify if a given feed has specific optional tags.

I see that I can do this:

Dim nodetest As XPathNodeIterator = navigator.Select("/rss/channel/item/*")

That will essentially give me access to all the various tags under a specific news ITEM. However, I just want to check one item. The only way I know to do this now is to do a While loop and read through ALL the items. Is there a quick way to find out what those are without looping through every item?

My code now looks like this:

While nodetest.MoveNext
Dim node As XPathNavigator = nodetest.Current
Dim tmp As String = node.Value

[Code].....