This document outlines procedures for detecting various contaminants in human cell cultures, including microbes, fungi, viruses, and mycoplasma. It describes microscopic and macroscopic checks for initial detection of bacterial or fungal contamination. Detection of viral contamination involves using PCR or other techniques to test for pathogens like HIV, HBV, and EBV. Mycoplasma contamination is detected using one of two methods - a PCR-based test or a luminometric assay that detects mycoplasma enzyme activity. Periodic screening is important to ensure cell cultures are free of contamination.