The Role of Local Public Health Laboratories

SYNOPSIS

Local public health laboratories (PHLs) serve many of the same roles as state PHLs and often perform many or portions of the 11 Core Functions and Capabilities of State Public Health Laboratories; however, they differ in several important ways. First, many local laboratories provide testing at the site of patient care (e.g., sexually transmitted infection clinics) or address local environmental issues (e.g., water quality). Second, local PHLs support the missions of local public health departments, which may differ from those at the state level. Third, local PHLs often serve as conduits, collecting specimens for various state-level screening and disease-control programs; and while they may not perform the testing, local PHLs are responsible for tracking specimens, ordering tests, and reporting results. Fourth, local PHLs often serve as surge capacity for state PHLs, particularly for testing to support emergency response. Last, local PHLs work with and are typically co-located in the local public health agency with other public health programs. Local PHL professionals work as a team with investigators, inspectors, and community and public health medical professionals and, thus, are poised to provide rapid and relevant responses to community needs.

Local public health laboratories (PHLs) serve an important and evolving role in supporting the broad mission of public health. To fulfill this role, local PHLs must be integrated with a diverse set of public health programs and services at the local, state, and national levels. Just as clinical laboratories provide a substantial proportion of the data used by health-care providers to diagnose, monitor, and treat patients, so do local PHLs generate much of the data used to make decisions and plans, evaluate programs, and provide local testing services. Local PHL data are also used by policy makers to assess the community's health status, identify health risks, and support public health program activities and decisions. The scope of responsibilities of local PHLs will grow in the future, not only in terms of the quantity of data generated, but also in the complexity of testing, and the evolution will differ from that of state and territorial PHLs. This article describes some of the current roles of local PHLs, how those roles may change, and some of the challenges these laboratories are likely to face in the next few years.

DESCRIPTION OF LOCAL PHL SERVICES

Because of their diverse roles in testing, the multiplicity of programs they support, and the lack of a single national accreditation program or registry, defining what constitutes a local PHL is not easy. Local PHLs represent a range of testing capabilities and organizational structures, from a small laboratory performing point-of-care testing to support a sexually transmitted infection (STI) clinic to a large laboratory providing comprehensive testing services (e.g., clinical, environmental, water, and food testing).

Accurate information regarding the functions and number of local PHLs is not readily available. In 2003, the Association of Public Health Laboratories (APHL) distributed a survey to approximately 1,800 local public health contacts¹ obtained from the National Association of County and City Health Officials (NACCHO), and 525 laboratories (29%) responded. In addition, APHL conducted four focus groups—one in person in California and the other three via conference calls—that drew feedback from an additional 74 local PHL directors from 13 states. Based on the information obtained from the survey and focus groups, APHL estimated that the total number of local PHLs was approximately 1,900.¹ Within these laboratories are an estimated 9,500 individual testing sites, making local PHLs numerically the largest component of the PHL network.

These findings can be compared with the 1992–1993 NACCHO survey in which 1,000 of 2,888 agencies reported providing direct laboratory services.² As reported in the APHL survey, laboratories in local public health agencies serving populations >500,000 performed tests in bacteriology (81%), tuberculosis (54%), mycology (42%), parasitology (58%), virology (45%), immunology (77%), environmental chemistry (61%), environmental microbiology (72%), clinical chemistry (62%), and occupational safety and health (32%); they also provided services in research and development (24%) and laboratory improvement and training (46%).¹

Public health agencies serving large populations are more likely to provide a range of testing services. The results of the 2003 APHL survey indicated that 82% of public health agencies provided programs or services that require laboratory testing. Overall, 70% of local public health agencies provided programs and services that require both environmental and human-specimen testing. The 18% of agencies that did not provide programs or services requiring laboratory testing were within smaller cities (defined as having populations <100,000).¹

Of the responding local public health agencies, 357 (68%) used in-house laboratory services for all or part of their laboratory testing supporting programs and services. Local public health agencies serving populations ≥100,000 performed 73% of their human-specimen testing and 55% of their environmental-sample testing in local PHLs, referring the remainder to other laboratories. Agencies serving populations <100,000 performed 46% of their human-specimen testing and 30% of their environmental-sample testing in local PHLs.¹

In addition to testing, larger local PHLs have capacity for other core public health functions. These may include research with local academic partners; training; didactic and experiential opportunities (e.g., internships and postdoctoral fellowship placements); local and state policy development through provision of laboratory data; and partnerships with local, state, federal, and sometimes international collaborators.

SUPPORTING LOCAL PUBLIC HEALTH SERVICES AND PROGRAMS

The roles of local PHLs in supporting local public health departments vary by the size of the community served, the relationship with the state public health department and laboratories, and community needs.

Many local PHLs provide on-site patient testing in settings such as tuberculosis diagnosis and treatment programs, STI clinics, and blood lead-poisoning screening and prevention programs. In this role they are, in many ways, more similar to clinical laboratories than are state PHLs. While some on-site testing in local public health agencies is complex, for the majority (69%) of local PHLs responding to the 2003 APHL survey, the type of testing performed was limited to tests classified by the Centers for Medicare and Medicaid Services as waived testing, which, by its nature, is low-complexity testing used for immediate evaluation and treatment of patients. More than 80% (60/71) of laboratories with high-complexity certification served populations ≥100,000 (23 of which served populations >500,000), whereas 84% (108/128) of laboratories certified to perform waived tests served populations <100,000.¹

Although both private-sector laboratories and local PHLs provide point-of-care testing, local PHLs differ from clinical laboratories in that they often serve confidential service programs (e.g., clinics for STI diagnosis and treatment or human immunodeficiency virus counseling and testing). Clients may seek government-funded confidential services to avoid insurance claims or the social stigma associated with seeking care from private-sector health-care providers. Local PHLs report results directly and rapidly to public health programs within the agency for expedited disease-control action.

Local PHLs prioritize testing for population-based disease-control efforts (such as those for tuberculosis) compared with the individual patient-oriented testing performed in clinical laboratories, which is mostly for diagnosis and treatment of acute illnesses (e.g., rapid tests for influenza or streptococcal pharyngitis) or for monitoring chronic diseases, such as diabetes. Furthermore, local PHLs often balance the clinical need for diagnostic testing with the public health need for surveillance screening through appropriate selection of testing methodologies. For example, gonorrhea diagnosis in the local PHL may include traditional culture to assure that an isolate is available for monitoring community emergence of antimicrobial resistance.

Local PHLs also support public health programs that do not provide direct patient care. These programs, in cooperation with state-level programs, involve implementation of community health standards, such as blood lead-poisoning screening, environmental lead-contamination investigations, communicable disease surveillance and testing, water supply safety monitoring, and local environmental testing. Many also support local public health food-safety and food service establishment inspection programs by providing food microbiology services, including investigations of outbreaks of foodborne diseases.

As noted in the APHL survey report, local PHLs are familiar with local health problems, enabling them to prioritize laboratory work and to address the immediate needs of the community. They also have strong ties and proximity to community clinicians, public health professionals, private laboratories, and the local media, allowing for enhanced local awareness in diagnosing clinical or environmental issues and a more efficient response in times of crisis, where necessary laboratory capacity exists. For instance, larger local PHLs may provide on-site assistance to health-agency inspectors for real-time enforcement of local codes and state statutes, and they have the capacity to assume the workload associated with many local emergencies.¹

ROLE WITHIN THE STATE PUBLIC HEALTH LABORATORY SYSTEM

All local PHLs are essential components of and contributors to the State Public Health Laboratory System (SPH Laboratory System). The intent of the SPH Laboratory System is to assure that laboratory data are available to support all 10 Essential Public Health Services.^3,4 As part of an SPH Laboratory System, local PHLs may contribute testing services in the statewide network (e.g., participating as a sentinel or confirmatory laboratory in the Laboratory Response Network [LRN] or screening children on-site for blood lead poisoning). Smaller local laboratories may collect and process specimens but forward them to the state PHL for testing, or perform preliminary testing and forward to the state PHL for confirmation. Larger local PHLs, in addition to providing immediate diagnostic and/or surveillance services for internal agency program needs, may also provide reference or confirmatory testing for community clinical laboratories or testing for neighboring public health agencies without comprehensive laboratory services and surge capacity for state PHLs, particularly in the area of emergency preparedness. As emphasized in the APHL survey report, larger workloads or programs at the local level (e.g., STI or blood lead-poisoning testing) would not be readily transferable to the state PHL.¹

As part of SPH Laboratory Systems, local PHLs may be connected to various feeder networks at the local level. Some states have developed a network or statewide PHL system, which provides the opportunity for state, regional, county, city, and other agencies to maximize resources and envision ways in which their services should evolve to meet community needs in the future. There are significant advantages to such a network, which can transform the way SPH Laboratory Systems meet the challenges of the future.

Opportunities for laboratory networking occur at the local level as well. Communication among local PHLs and local clinical laboratories provides an opportunity to exchange information and data related to ongoing public health issues and investigations, and to identify unmet community laboratory service needs. Local PHL interaction with hospital systems can be used to communicate to clinical microbiology directors a number of issues, such as continuing education, training, and laboratory quality-improvement programs.

Another role of local PHLs is assisting other local health departments in meeting regulatory requirements. Expertise in laboratory quality-management systems is often lacking at the local public health agency, especially in those that provide only waived tests to support on-site patient management, making it difficult to meet regulatory requirements. In Michigan, three sophisticated local PHLs provide regional laboratory quality oversight and meet regulatory requirements through the use of the Clinical Laboratory Improvement Amendments option of the Umbrella Public Health Certificate to neighboring local public health agencies.⁵ Under this option, an unlimited number of testing sites can perform up to 15 waived tests. Participating local public health agencies contribute to the cost of centralized quality-control review, site survey, and other quality-management activities provided by the regional laboratory. The state PHL contributes to the regional laboratory system by providing technical and quality-assurance expertise, model quality manuals, standard operating procedures, and an internal proficiency-testing program. This regional laboratory system has improved quality of testing performed in local public health agencies, especially rural public health clinics without access to clinical laboratory services locally.⁶

Other roles of local PHLs include training practicing laboratory professionals and hosting postdoctoral researchers and interns. Local PHLs may also serve as intermediaries in communicating state-level PHL-relevant policies to local clinical laboratories and as conduits for reporting local testing needs to state and federal programs.

ROLE WITHIN THE NATIONAL LABORATORY SYSTEM

As components of the National Laboratory System, local PHLs serve as feeders to federal laboratories, such as the Centers for Disease Control and Prevention.^7,8 This role is not limited to serving as a source of specimens; local PHLs also collect and transmit test results and other data to state and federal surveillance programs. Larger local PHLs may participate in national/global laboratory networks, such as PulseNet, the LRN, and the data exchange system/repository known as eLEXNET.^9,10 With the recent appreciation of the overall health status of populations, reportable diseases and conditions, and the evaluation of public health interventions, this role is likely to grow in the future.

During the past decade, many local PHLs served in a new role—providing surge capacity for emergency response, particularly in the area of select-agent testing, as part of the LRN. By moving testing closer to the populations that need it, the steps of collecting specimens and forwarding them to a state PHL are removed, and test turnaround time is improved. Equipment made available through participation in the LRN may also have dual use for local priorities (e.g., testing for influenza virus and Bordetella pertussis). Moreover, technical training provided by the LRN to local PHL personnel allows them to develop and maintain expertise in molecular and other types of testing that may not have been traditionally offered by local PHLs. To some extent, this type of testing is another form of surge capacity in that it increases the availability of laboratory testing for public health purposes.

LOCAL PHL CHALLENGES

Many of the challenges facing local PHLs are similar to those facing state PHLs; however, because many local PHLs function on a smaller scale and may have access to fewer resources than their state counterparts, these challenges may be exacerbated at the local level. For example, expanding expertise and the scope of testing requires state-of-the-art laboratory facilities, particularly for molecular testing and the security requirements for select-agents testing. Many local PHLs do not possess or have access to sufficient space, and existing space often is not amenable to renovation. Resources needed to address biosafety and biosecurity requirements are also of concern. Information technology (IT), including hardware and laboratory information system software, is expensive and may require infrastructure that is not available to many local PHLs. IT is an area where new technology solutions are needed to meet training and data-management needs. Regionalization, specialization, or sharing resources (e.g., instrumentation) among geographically related local PHLs to address common public health issues may all be options to address some of these concerns in the future.

Local PHLs also face the challenge of an aging workforce and the difficulty associated with recruitment and replacement of existing staff. Like state PHLs, many local PHLs are finding it difficult to attract qualified and appropriate scientific leadership to carry their institutions into the coming decades.

LABORATORY CERTIFICATION AND ACCREDITATION

As with the SPH Laboratory System and territorial PHLs, there is no single national accreditation for local PHLs. Local PHLs that perform testing for purposes of direct patient care (e.g., to support the functions of an STI or tuberculosis clinic) have CLIA certification directly or through another deemed entity. Some local PHLs also receive certification or accreditation for environmental testing or water testing. The lack of a single national accreditation program for both state and local PHL professionals results in a number of issues. First, it complicates efforts by laboratory directors to implement a single quality-assurance or data-management program. Second, proficiency-testing programs do not offer products that cover the full scope of testing provided by PHLs. Those designed for clinical laboratories, particularly hospital laboratories, may not include all of the tests used by PHL professionals (e.g., a dark-field test for syphilis). Lastly, the lack of a national accreditation program may complicate efforts of laboratory directors to establish productivity and other benchmarks, and, therefore, compare costs and other management metrics. For laboratories with a role limited to supporting specific patient-care activities, certification under CLIA may be sufficient. For larger laboratories, however, a national accreditation program is needed.

CONCLUSIONS

Local PHLs may differ greatly in their size and function but ultimately are united in their support of the 10 Essential Services, as determined by the needs and limitations of their local jurisdictions. Local PHLs play an important role in the public health system as the only laboratories that exist solely with the incentive, mission, and community ownership to address laboratory services for local public health and safety. It is likely that this role will grow in the future, as national, state, and territorial laboratories focus their efforts on more complex testing, shifting less complex testing and testing needed for the immediate evaluation of patients to local PHLs.

In addition to the practical challenges of fulfilling this new role in the public health system, local PHLs will need to address the challenges of meeting certification and accreditation standards, providing a broader scope of services, and assuming some of the responsibilities of state and territorial laboratories. For local laboratories to fulfill these new roles successfully, some may need to make fundamental changes in management, staffing, funding, informatics, and infrastructure. These challenges will require the guidance of what may be a new type of laboratory director who is likely to play a very different role than in the past.