PCR is a well-established method for detection of microbe specific, nucleotide sequences. It is very sensitive and specific. However, it can only detect what one has probes for. Culture can identify any bacteria and yeast that are aerobic or facultative anaerobes and abundant enough to grow out. Microscopy can identify any parasites that can be detected via standardized, high-quality O&P. The combined methodologies are the paragon of complementation.