ObjectiveTo establish a method that can eliminate the pollution of endogenous nucleic acid in the real-time quantitative polymerase chain reaction (PCR) reaction system, which can be used to reduce or eliminate the false positive rate of real-time PCR assay in detection of postoperative intracranial bacteria infection.MethodsAt first, eliminated the pollution of endogenous nucleic acid in the real-time PCR reaction system. Then, with mixed bacteria DNA as a template, multiple PCR was used to specifically identify the gram-negative bacteria. Meanwhile, evaluated the text line and sensitivity of the multiple PCR after eliminating pollution in detecting the DNA of the mixed bacteria.ResultsThe method established could quickly eliminate the pollution of endogenous nucleic acid in the real-time PCR reaction system, and it didn’t affect the Taq enzyme activity and the amplification efficiency in PCR system, with the minimum detection limit of 102 CFU/mL (Staphylococcus aureus and Pseudomonas aeruginosa), which was the same to the culture method. The enzyme cutting method had no significant effect on the activity and amplification efficiency of the enzyme in PCR system, It had no effect on PCR reaction system and primer specificity (Ct=32, ΔRn=200). However, the filtration method significantly reduced the PCR amplification efficiency (Ct=32, ΔRn=150).ConclusionsThis method can easily and rapidly eliminate the pollution of endogenous nucleic acid in the real-time PCR reaction system, and greatly reduce the false positive of PCR detection. It is able to timely and accurately diagnose the intracranial bacteria infection, which is significant for clinical testing.