Do you have the flexibility to stall for 20 min? I want to be sure this isn't a dropping numbers. If you could not do anything -- especially don't feed Shadow -- and get another test in 20 - 30 min? If the next test is pretty much the same or rising, it will be fine to shoot providing you have strips and high carb food and will be around to monitor should Shadow want to see some green.
You'll want to get a +1 and a +2 test since this is the lowest you would be shooting.