Radon measurement protocol is slightly different for the general public than it is for a real estate transaction.  You can obtain a full copy of each protocol from the following EPA web links:

• A Citizen's Guide to Radon
• Home Buyer's and Seller's Guide to Radon

One of the biggest obstacles in radon testing for a real estate transaction is that sellers are often unaware of their responsibilities regarding the testing protocol, and many times they inadvertently violate the protocol.  This can add several days to the test or even worse, it can cause a need for a new test and a second fee that the buyer may not want to incur.  The seller may not want to pay for it either and now you have one more issue that can cause problems in the transaction.  Fortunately, this is easily avoided.   The protocol that the seller must maintain begins 12 hours prior to the test and throughout the test is referred to as "closed house conditions."  The violation of this protocol is most often opening windows.  They must be kept closed during this time period. There are several other ways to violate closed house conditions, click on the image.