Table 2.

Pre-analytical parameters influencing the quality of biological samples and hindering the quantitative analysis of potential biomarkers and drug targets

Pre-analytical parameters	Source of errors	Proposed solutions
Medication before surgery and type of anaesthesia	Influence on gene or protein expression	Detailed documentation and account for it during analysis
Time of vessel ligation	Time is unknown	Detailed documentation
Time of specimen removal	Time is unknown	Detailed documentation
Location of specimen removal (e.g. centre of a tumour or periphery)	Tumour area not homogeneous	Comparison only between homogeneous pieces, detailed documentation
Time and temperature of transport e.g. to pathology	Time and conditions are unknown	As fast as possible, detailed documentation
Time until fixation	Time is unknown	As fast as possible, detailed documentation
Type and duration of fixation	Cross-linking by formalin	Novel fixation methods
Temperature and duration of fixation	Not standardized	Standardized conditions, detailed documentation