Pre-analytical variables are those that affect the specimen before the actual testing begins. Some of the pre-analytical variables to consider with molecular testing include those that are applicable to all clinical specimens but should be emphasized when discussing molecular methodologies. Some of these include but are not limited to:
Receipt of valid order
Proper patient identification
Proper venipuncture procedure for blood collection
Use of correct anticoagulant
Collection of correct specimen type (eg - plasma, serum, whole blood)
Order of draw
Proper storage
Proper transport
Procedures if there is a delay in testing and/or transport
