Obtaining Maximum PCR Sensitivity and Specificity
from Cameron N. Gundry and Matthew D. Poulson writing in PCR Troubleshooting and Optimization: The Essential Guide:

PCR is a highly sensitive and specific technique used in molecular biology laboratories everywhere. It is able to provide near 100% sensitivity and specificity with appropriately designed assays in controlled situations. However, results do not always match this potential. The most common problems in PCR arise from overlooking basic principles in assay design and optimization. Maximum PCR performance depends on key factors which include: 1) choosing an appropriate detection system, 2) using available software for the best primer and probe design, 3) assessing sample quality and controlling inhibitors, 4) avoiding amplicon and environmental contamination, 5) optimizing for reagent quality and concentration, and 6) modifying the thermal cycling protocol for optimal sensitivity and specificity. Addressing all of these factors will aid the investigator in designing high quality PCR assays.

Further reading: PCR Troubleshooting and Optimization: The Essential Guide

Key words: PCR Optimization, PCR Sensitivity, PCR Specificity, PCR detection system, PCR Software, PCR Primer design, PCR probe design, PCR inhibitors, Thermal cycling protocol