Centralizing Microbology Laboratorian

The structure and location of diagnostic laboratory services have undergone a significant shift in recent years. As part of laboratory stewardship, laboratories continually review their scope of service in order to better utilize healthcare resources while still meeting the needs of patients and clinicians.

In part due to this stewardship model, consolidation and centralization of laboratory services increasingly are becoming the norm. The goal of this article is to provide thoughtful discussion of the relevant issues surrounding centralization and consolidation of microbiology services for laboratories that might be considering such a model.

Why Consider Consolidation?

Consolidation enables a laboratory to standardize pre-analytic, analytic, and post-analytic practices in microbiology and offers cost savings on instruments, reagents, and personnel. The many arguments for and against consolidation have been outlined in a number of excellent articles (1–5). Importantly, a centralized laboratory can provide a single set of orderable tests and the guidance to collect appropriate specimens for those tests through a concentrated, and highly integrated, center of expertise.

For example, testing for antibiotic-associated diarrhea caused by Clostridioides difficile requires a liquid stool specimen. Many laboratories use the so-called “stick test” to ensure that proper specimens are tested—specimens in which the stick falls over would be tested, but those in which the stick remains upright would be rejected as formed stool. This approach can be easily standardized for one staff of microbiologists in a centralized laboratory. 

Cost savings is a significant consideration as well. In a de-centralized model with multiple low-volume sites, the number of instruments of each kind also multiplies, such as molecular platforms, antimicrobial susceptibility testing (AST) instrumentation, and pathogen identification systems. Quality control (QC) reagents also need to be available at each site. Even though laboratories should account for reagent volumes needed for their testing menus, with duplicate testing occurring at multiple sites there is bound to be waste in the form of extra reagents on hand.

Consolidating several microbiology laboratories into one centralized facility allows a healthcare system to allocate a single set of financial resources for its diagnostic microbiology services: one staff of microbiologists, one set of QC testing for each assay, and the appropriate amount of instrumentation to account for current and projected testing volume. Healthcare systems also can leverage bulk purchasing to secure lower reagent pricing, with minimal waste due to off-site testing.

In most cases, personnel costs account for the largest piece of a laboratory’s budget, and this is another area in which centralization eliminates duplicate effort and cost. For example, in many cases culture reading at a centralized laboratory can occur on three shifts whereas at off-site laboratories this task may only take place during the first shift. This system can allow for culture workup on a first-in first-out basis when the plates are ready to be reviewed, rather than batch reading when staff members are available.

Patient care takes a team of healthcare professionals, including physicians, nurses, pharmacists, and laboratorians. Consolidating microbiology services allows for subject matter expertise to be present in one location, with a trained microbiologist staff available to perform testing and report results according to a single, standardized operating procedure. An experienced micro­biologist, with demonstrated skills in operational oversight and personnel management, also would be available to drive managerial success.

Importantly, in a consolidated services model, microbiology medical director(s) would be available in a centralized location with the rest of the microbiologist team. Hospital systems should have well-trained, professional scientists who are board-certified in medical microbiology available to provide vision for their centralized laboratory, guidance on standard-of-care-based improvements to the testing menu, and clinical consultation on microbiology testing to healthcare workers (6).

Other important ways a single, consolidated staff yields greater efficiencies include proficiency testing through the College of American Pathologists (CAP) or alternative proficiency testing services, employee training and annual competencies, continuing education opportunities, project work such as validating new tests, and preparing for inspections by accrediting agencies.

New Challenges With Consolidation

There are many advantages to consolidating clinical microbiology services; however, one must also consider trade-offs of such a model that create unique challenges.

In a decentralized model, microbiology testing is physically located closer to the patients at all facilities, clinical care teams have direct contact with each laboratory, there is no need to transport microbiology specimens long distances, and staff members can respond faster to local questions and concerns.

The impact of consolidation on clinician practice also should not be overlooked. Infectious diseases (ID) practitioners, especially, are accustomed to visiting their institution’s microbiology laboratory prior to rounding on patients each day. This interaction provides the ID physicians with up-to-the-minute information on their patients and allows them the opportunity for special requests in real time.

Moreover, visualization of culture growth also reinforces important microbiology concepts like optimal growth requirements, normal flora of various anatomic sites, pathogen quantitation, and inherent antimicrobial resistance. Absence of this interaction is a missed opportunity not only for ID physicians but also for microbiologists: Centralized laboratory services can create a culture of disjointed patient care. Plate reading can become a rote, iterative activity, giving microbiologists the sense of no longer being connected to patients on the other side of petri dishes.

Another consideration is that even with a centralized microbiology laboratory, some microbiology testing must continue at off-site locations. Clinical impact should drive the decision to keep or send microbiology work to a centralized laboratory.

For example, rapid antigen testing for pediatric pharyngitis caused by group A Streptococcus should be performed as a STAT test because immediate antimicrobial therapy lowers a patient’s infectivity while also reducing development of supparative and nonsupparative sequelae. Sending this testing to a centralized laboratory would slow down testing, delay the start of antibiotics, and put patients at increased risk.

Logistical issues also can be problematic within a healthcare system, especially when it comes to transporting specimens to a centralized location. Courier costs, schedules, and routes are of critical importance. Timely inoculation of specimens into microbiology culture media provides the best opportunity to recover infectious disease pathogens. Likewise, delays in transport and extreme environmental conditions can lead to false-negative culture results. Transporting specimens also raises the risk they’ll get lost en route to the central laboratory.

Excellent communication between laboratories and couriers, remote and central hospitals, and ordering clinicians are essential to successfully managing these issues, especially if problems arise.

Finally, while centralizing and concentrating expertise in one location offers benefits, it also has the potential to create an expertise vacuum at outlying facilities. In a centralized laboratory, the microbiology director and manager should not remain siloed. Rather, they must endeavor to maintain a visible presence within their healthcare system, making every effort to attend grand rounds, journal clubs, service line meetings, and the like in order to speak about microbiology testing services. These professionals must also collaborate with the full range of healthcare services to ensure that standard of care is met for every patient.

The Automation Question

Total laboratory automation (TLA) in microbiology is becoming commonplace for high-volume and lower-volume laboratories alike. With TLA, a laboratory receives specimens, inoculates them into appropriate culture media, and sends them via conveyer belt to an incubator that takes high-resolution images of the plates at regular intervals. Microbiologists read plates digitally and electronically order testing to be performed for identification and AST, which can be performed manually or automated, depending on the types of enhancements a laboratory purchases as part of its automation system.

The decision to implement TLA is beyond the scope of this article. However, implementing automation in microbiology can impact the decision to centralize microbiology services. A consolidated laboratory that uses TLA is likely to have better efficiency: Cultures showing no growth can be dismissed as negative with the click of a button, and microbiologists would only need to touch those cultures with significant pathogen growth.

Automation in microbiology laboratories is a relatively new concept, with the general model being that specimens are sent to the processor for inoculation and plates are read on-site. However, in the future microbiology automation may offer scaled-down versions of the processor and incubator maintained locally while enabling microbiologists at centralized laboratories to read plates.

This would alleviate courier delays, non-viable organisms, transporting inoculated plates, and other problems. However, this possibility would require much thoughtful consideration prior to implementation.

A Centralization Checklist

Once a laboratory makes the decision to centralize microbiology services, leaders need to tackle several strategic hurdles. The following is a list that we have found helpful.

Get Constituent Buy-In

The stakes could not be higher when it comes to microbiology services. Hospital leaders, clinicians, and laboratory staff must all accept the centralized model. Leaders must understand the rationale for such a model and be willing to provide the necessary financial and personnel resources to succeed. Laboratory professionals should also be prepared to provide data to clinicians demonstrating the centralized laboratory’s successful performance.

Laboratorians will also need to educate clinical care staff about the risks of a centralized laboratory, such as specimen transport issues, and plan for how those risks will be mitigated.

Within the affected laboratories, staff must accept that organizational change will necessarily occur when transitioning to a centralized model. Shift start times, productivity expectations, workload, and the like all will probably differ post-centralization.

Critically, the healthcare system must decide what the standard of care will be for all patients in the organization, and the laboratory must be given the resources necessary to provide that standard.

Develop a Communication Plan

Questions and concerns from outside facilities—both generalist laboratorians and clinicians—will undoubtedly arise. These run the gamut from specimen collection requirements, to clarification of results, to requests for additional testing. The laboratory must decide between providing a single telephone number for calls directly to the microbiology team or calls to a client services division. Alternatively, email, secure text paging systems, or other electronic options may be considered.

Address Specimen Management

A curated electronic resource to guide appropriate specimen collection and submission should be available to clinical care teams. Additionally, a robust continuing education program on issues of specimen collection should be part of a laboratory’s competency program. Using these two tools together in a consolidated laboratory can minimize delays due to specimen collection.

Upon receipt of an appropriate specimen, the question to plate or not to plate? becomes significant. To respond appropriately, laboratory staff need to know several things, including the distance traveled between a collection site and the centralized laboratory, the reliability of transport devices for maintaining organism viability, and whether offsite generalists have been trained to inoculate specimens into culture.

If specimens are to be inoculated locally with plates sent to the centralized laboratory for workup, portable incubators will be required during transport. The incubators also will require temperature monitoring, resulting in additional effort from the laboratory.

The laboratory must also determine how it will handle performing and reporting Gram stains. In certain clinical situations a timely Gram stain can be the difference between life and death for a patient because it guides prompt and appropriate empiric antimicrobial therapy. Likewise, generalists at local sites need to maintain competency in performing and reporting Gram stains. There may be a role for internet-based distance microscopy, wherein a microbiologist at the centralized laboratory reviews the Gram stain result before to issuing the report to the local laboratory.

Make Decisions on Rapid Testing

Clinical impact of the result should drive the decision to perform rapid kit testing locally or at the centralized laboratory. One rule of thumb is to perform locally any testing that requires a result in less than 3 hours. Examples of testing that meets this criterion include streptococcal antigen testing for suspected bacterial pharyngitis and cryptococcal antigen testing on cerebrospinal fluid for suspected meningitis.

The laboratory also will need to tackle how to handle rapid molecular testing. Sample-to-answer molecular testing is available commercially as either moderate complexity or waived testing. Rapid identification of positive blood culture pathogens and suspected influenza are two clinically relevant examples. The expertise of the personnel performing these assays should guide the decision to provide such testing. Questions will undoubtedly arise from the results of these tests, and the ability to respond in real time is critical.

Optimize Courier Schedules

The healthcare system must decide between using an internal fleet of couriers or a third-party provider. Courier routes and schedules must keep the risk of specimen transport issues and delays as low as possible. A reliable electronic tracking program helps reduce the risk of lost specimens.

Labs also need to determine the acceptable length of time that a specimen can sit idle prior to being transported. The laboratory must perform validation studies to account for the loss of organism viability. These studies must be performed regardless of whether the system decides to ship specimens or inoculated plates to the centralized laboratory.

Assign Responsibility for Result Review and Corrective Action

If a healthcare system decides to centralize most microbiology testing and perform just a few tests locally, it will need to determine how to perform this testing, how to report the results, and how to perform corrective action when errors occur. The microbiology manager and director should be responsible for these decisions, regardless of the operational/managerial infrastructure present at local laboratories.

Design With Regulatory Compliance in Mind

Healthcare systems must consider how they will manage regulatory compliance, both on a continuous basis and when accrediting inspections occur. If a central lab performs all microbiology testing, the scope of a CAP inspection checklist rests entirely on that laboratory. However, if local labs perform minimal microbiology (e.g., inoculation of specimens, Gram stains, rapid testing), these off site laboratories are subject to a limited microbiology checklist that still requires following many regulations.

There is a specific CAP requirement for supervision of micro­biology services that must be considered. Two years of microbiology experience are required to supervise microbiology services, even if the only task being performed is the Gram stain. The laboratory must consider how compliance with this requirement is maintained once microbiology services are no longer being performed locally. Other regulatory issues under CLIA, JCAHO, COLA, and state agencies must also be considered.


Centralizing microbiology services can be achieved successfully with careful preparation. Chief among the many concerns we’ve raised is clinician buy-in: Clinical care staff must be able to rely on timely, accurate results from microbiology laboratories regardless of their location.

Before making such a conse­quential decision for a health system, laboratory leaders must reflect on many issues of logistics, resources, and regulation in order to determine if centralization is the right model for the healthcare system and, importantly, the patients being served by that system.

Corrie C. Simons, MLT(ASCP)M, is the manager of the clinical microbiology laboratory at Duke University Health System in Durham, North Carolina. Email: [email protected]

Gerald Capraro, PhD, D(ABMM), is the medical director of the clinical microbiology laboratory at Carolinas Pathology Group, Atrium Health, in Charlotte, North Carolina. Email: [email protected]


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