Syndromic and point-of-care molecular diagnostic testing methods have revolutionized infectious disease testing by permitting the simultaneous detection of multiple pathogens and drug resistance mechanisms directly from clinical specimens and positive blood cultures.
Syndromic testing panels currently include those designed for the detection of pathogens responsible for bloodstream, central nervous system, gastrointestinal tract, and respiratory tract infections as well as some biothreat agents.
Point-of-care molecular diagnostic systems afford providers the ability to generate laboratory-quality results without the need for confirmatory testing of negative specimens.
Implementation of syndromic and point-of-care molecular infectious disease testing methods has curbed the unnecessary use of antibiotics, strengthening antimicrobial stewardship practices.
Development of methods for the detection of infectious diseases beyond those that are detectable by current technologies is an area of investigation.
For decades, the clinical laboratory diagnosis of many infectious diseases relied solely on time-consuming and often labor-intensive manual cultivation-based, microscopic, and immunoserologic methods that required experienced technical personnel to perform and interpret. The introduction of semiautomated and fully automated microbial phenotyping systems in the later part of the 20th century vastly improved the processes of bacterial and yeast isolate workup by decreasing identification and antimicrobial susceptibility testing turnaround times (TATs); however, the detection of many viruses and parasites still required traditional techniques. Subsequent improvements to automated platforms, including the refinement of the automated expert systems used by these devices to generate and interpret data, led to further decreases in TATs and a concomitant increase in culture throughput.
In the 1990s, the era of molecular diagnostics was ushered in with the introduction of nucleic acid analysis methods, including the hybridization protection assay (eg, AccuProbe, Salem, MA) for the identification of isolates and polymerase chain reaction (PCR) for the detection of pathogens directly from patient specimens
. Later, the implementation of real-time nucleic acid amplification chemistries permitted both faster pathogen detection and the enablement of nucleic acid quantitation
. These methods quickly migrated from research laboratories into clinical laboratories, first as laboratory-developed tests or so-called home brew tests. This revolution enabled laboratorians to more precisely identify the causes of infectious diseases by detecting pathogen-specific nucleotide sequences in cultured isolates and clinical specimens. Many of these methods proved to be far superior in terms of accuracy and result TAT compared with cultivation-dependent approaches, especially for the identification of viruses. Over time, these methods also underwent refinements that included the adaptation of several assays to automated platforms, allowing users to minimize the manual handling of specimens and reaction components.
One recent advancement in pathogen detection is the syndromic approach in which groups of pathogens are tested for simultaneously in a single reaction vessel. These assays incorporate components of older methods, including real-time PCR; however, rather than ordering separate tests for various pathogens, the syndromic tests allow simultaneous detection of a variety of agents that are associated with a specific disease syndrome
The newest systems are those that allow users to perform laboratory-quality molecular testing at the point of patient care, a major advancement that has moved molecular pathology to the forefront of modern diagnostics. Many Clinical Laboratory Improvement Amendments (CLIA)-waived point-of-care (POC) systems are now available and permit rapid result reporting, enabling prescription of targeted treatment at the time of clinic visit. The current assays on these platforms largely target infections diagnosed in the ambulatory setting such as influenza and streptococcal pharyngitis.