Pre-analytical error

· Incorrect sampling method and sampling location

· Inappropriate material for sampling

· Inadequate sample volume

· Inadequate or improper use of PPE

· Lack of human resources

Analytical error

· Low quantity and quality of extracted RNA

· RNA contamination during extraction

· Pipetting errors

· Use of inappropriate sample volume for cDNA synthesis and

· Improper storage of PCR reagents

Post-analytical error

· Misinterpretation

· Incorrect determination of exact baseline and threshold

· Amplicon contamination