Check if userid is already in claims mode

Hi,

How to check if user account id (domain\username) is already converted to claims account?

I have tried the below code:

 SPClaimProviderManager ClaimManager = SPClaimProviderManager.Local;
if (ClaimManager != null)
{
  try
  {   
string strUserLanID;
 SPClaim claim = new SPClaim(SPClaimTypes.UserLogonName, strUserLanID, "http://www.w3.org/2001/XMLSchema#string", SPOriginalIssuers.Format(SPOriginalIssuerType.Windows));
 strUserLanID = ClaimManager.EncodeClaim(claim);
  }
  catch (Exception ex)
  { 
  }
}

If the strUserLanID is of type "domain\username", the above code works, but if the strUserLanID is of type "i:0#.w|domain\username", then i get the error as username is not unique. How to check if the userid is already in claims mode?

Thanks