I decided to dig into this a bit further.
TRACE:In doing so, I found that I could monitor our SQL Server DB to determine this.
I have only found two places where the transaction isolation level is appearing:
1 - Sessions:Existing Connection.Text Data
2 - In a deadlock trace as part of the XML output.
If anyone can find it elsewhere, I'd love to hear from you. However, this makes sense, since this is more-or-less controlled at the session level.
If found that
DBCC USEROPTIONSwould give me the *default* TIL for the db, but that if that TIL was altered by the session, it would not reflect that.
To get the TIL for *your session*, you can run the following query:
SELECT CASE transaction_isolation_level WHEN 0 THEN 'Unspecified' WHEN 1 THEN 'ReadUncomitted' WHEN 2 THEN 'Readcomitted' WHEN 3 THEN 'Repeatable' WHEN 4 THEN 'Serializable' WHEN 5 THEN 'Snapshot' END AS TRANSACTION_ISOLATION_LEVEL FROM sys.dm_exec_sessions
Credit to StackOverflow question and answer here: http://stackoverflow.com/questions/1038113/how-to-find-current-transaction-level