How do I return a string from a uniqueidentifier field using node-tds?

I'm using nodejs + node-tds to connect to a SqlServer 2008r2 express database. I'm retrieving an object with a uniqueidentifier and returning the entire object as json.

I can retrieve the row fine, but when I try to serialize the response to json, it comes out funky:

{
  "Id": "�<�E�ԃM��\u0000ؚ��J",
  "RealName": "Zachary Yates"
}

Here's the code I'm using:

var q = conn.createStatement("select u.Id, u.RealName from [User] u where u.Id = @id;", 
{
    id: { type: "uniqueidentifier" }
});
q.on("row", function(row) 
{
    var user = 
    {
          Id: row.getValue("Id").toString()
        , RealName: row.getValue("RealName")
    };
    res.json(user);
});
q.execute({id: uid});