They may be similar, but from what I've read, a PCR test is not done by taking a blood sample - only nasal swabs and saliva samples.Seralogic tests and PCR tests are similar and both imperfect:
Different paths to the same destination: screening for Covid-19
The three main types of Covid-19 test - PCR, LFT and antibody - all work in different ways to diagnose infection or assess immunitywww.medicaldevice-network.com