Clinical microbiology is a discipline that encompasses a broad range of testing methodologies, and it is complex in terms of organisms and methods used to isolate and identify them. Although significant improvements in testing methodologies have been made, clinical microbiology remains heavily reliant on culture-based methods and phenotypic methods for identification of culture organisms. The wide variety of pathogens and testing methods that are available makes microbiological testing challenging, and thus error detection and correction are important components of quality microbiology laboratory testing. Errors may occur at all stages of testing (pre-analytical, analytical, and post-analytical), and an error in one stage of testing is likely to overlap with or lead to errors in other stages (e.g., incorrect specimen collection can lead to culture, identification, and reporting of organisms that are not involved in the disease process and to incorrect or unnecessary antimicrobial therapy as a result). In the clinical microbiology laboratory, as in every other discipline, the frequency of analytical errors has been reduced considerably with the implementation of quality control and quality assurance programs. Despite the improvements in microbiological testing, microorganisms remain a constant challenge, and errors do occasionally occur. This chapter discusses some of the common interferences in the clinical microbiology laboratory.
