PCR (polymerase chain reaction) is a technique that helps in the amplification of DNA. A small amount of DNA can be amplified by PCR. The pathogens that are difficult to culture in-vitro or require a long time to culture can be easily traced with this technique. So, this method helps in the early diagnosis of bacterial or viral infections in humans.
A serum analyzer is used to analyze the components of the blood serum. Generally, these tests are not as accurate as PCR and may not give early diagnostic results.
CT scan (computed tomography scan) is a medical imaging procedure that uses a computer-processed technique to observe the cross-sectional images of a tissue or organ without cutting.
DNA sequencer is a scientific device used to sequence DNA.