@nbpt100
Doing a current test can be done using either pole of the battery but the reason the negative side is usually used is due to safety reasons. If the test connections are placed on the negative side then if any of the connections come in contact with chassis ground nothing will happen, except perhaps the meter may get bypassed and have no reading as a result of that. But imagine what would happen if the positive side was used and any of those connections came in contact with ground. Need I say more?
Like others have already said, there appears to be an excessive parasitic drain on the battery while the car is parked and a current drain test needs to be done. Normal current draw on the battery should be less than 50 milliamps when systems are in the sleep mode.