Pre-examination variables are those that affect the specimen before the actual testing begins. Some of the pre-examination variables to consider with molecular testing include those that apply to all clinical specimens but should be emphasized when discussing molecular methodologies; some of these include but are not limited to:
Receipt of a 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, proper type of swab/approved body site)
Order of draw
Proper storage (temperature)
Proper transport (and proper transport media)
Procedures if there is a delay in testing and/or transport
