Sensitivity of PCR is

The sensitivity of PCR is 1-10 pg/l.
The polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it.
PCR was invented in 1983 by the American biochemist Kary Mullis at Cetus Corporation. The high sensitivity of PCR permits virus detection soon after infection and even before the onset of the disease.
PCR assays can be performed directly on genomic DNA samples to detect translocation-specific malignant cells at a sensitivity that is at least 10,000 fold higher than that of other methods.