Pathology's contributions to disease surveillance: sending our data to public health officials and encouraging our clinical colleagues to do so.
Abstract: * Pathology and clinical laboratories produce many types of data and information that are of relevance in protecting the health of the public. Electronic linkages between laboratory/pathology information systems and public health surveillance databases help ensure that these data reach the appropriate responder rapidly, completely, and accurately. Many efforts are underway to facilitate the flow of data from laboratory/pathology data sources to public health systems. Likewise, pathologists can encourage the contribution of clinical data from other parts of the health care enterprise. Chief complaint data from the emergency department and usage of over-the-counter medications from the retail pharmacy are useful for real-time population health surveillance. Having directly advocated transmission of data from our laboratories and facilitated other departments' participation in the public health surveillance network, we can also serve the public's health in other ways. Public health jurisdictions have a great need for staff with the skill sets of an experienced laboratorian. So, plan to contribute: data and talent.

(Arch Pathol Lab Med. 2009;133:926-932)
Article Type: Report
Subject: Public health (Management)
Pathology (Practice)
Sentinel health events (Methods)
Epidemics (United States)
Epidemics (Evaluation)
Author: Aller, Raymond D.
Pub Date: 06/01/2009
Publication: Name: Archives of Pathology & Laboratory Medicine Publisher: College of American Pathologists Audience: Academic; Professional Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 College of American Pathologists ISSN: 1543-2165
Issue: Date: June, 2009 Source Volume: 133 Source Issue: 6
Topic: Event Code: 200 Management dynamics Computer Subject: Company business management
Product: Product Code: 8000120 Public Health Care; 9005200 Health Programs-Total Govt; 9105200 Health Programs NAICS Code: 62 Health Care and Social Assistance; 923 Administration of Human Resource Programs; 92312 Administration of Public Health Programs
Geographic: Geographic Scope: United States Geographic Code: 1USA United States
Accession Number: 230152021
Full Text: Pathology and laboratory medicine make many critical contributions to disease surveillance and other aspects of public health. In this paper, I focus on how data we produce in the laboratory facilitates the identification of established or emerging disease(s) and evaluation of potential disease outbreaks, and how we can encourage our colleagues in other clinical departments (eg, the emergency department) to contribute data for disease surveillance.

First, it is important to recognize that public health is a very diverse field. At the same time, there are activities commonly associated (in the mind of the casual observer) with the term public health that are not included in public health.

The common theme of public health is to improve the health of the overall public in a variety of ways. It takes the point of view of an entire population, rather than the individual patient. It is about assessing, protecting, and improving the public's health, but not about using public funds to provide medical care to individual patients (except when, in doing so, we can directly block disease transmission--eg, tuberculosis). Public health also includes disease/condition registries, early warning systems for disease outbreaks, and electronic notification.

At the same time, pathology is an exceedingly diverse field. Indeed, one might even agree with the definition of pathology from the long-time chair of Pathology at Yale University School of Medicine, Harry S. N. Greene, MD--as orally related to me in about 1982 by Thomas Lincoln, MD. "Pathology is ... what a pathologist does." There is simply no other definition that incorporates all the diverse activities of (1) the director of the National Library of Medicine, (2) the creator of the world's standard medical nomenclature (the Systematized Nomenclature of Medicine [SNOMED]), (3) the editor of the leading medical journal (Journal of the American Medical Association), (4) the owner of a premier laboratory information system vendor (Sunquest Information Systems, Tucson, Arizona), (5) head of a public health disease surveillance unit and, of course, (6) the diagnosticians providing the basis for 95% of the oncologic care in the United States and the laboratorians who have built the US laboratory system into the world's finest.

Nevertheless, for the purposes of this paper we will primarily focus on the traditional functions of pathology:

1. Surgical pathology/cytopathology, where individual diagnoses of tissue specimens are rendered via personal service.

2. Forensic pathology--why and how did they die?

3. Clinical pathology--assuring usefulness of a variety of diagnostic and monitoring assays.

In addition, we will describe other clinical data sources that have proven useful in disease detection systems and for which the pathologist can play an important role as an advocate promoting connection of his/her clinical enterprise to the jurisdiction's public health database.

In connecting pathology--or other clinical practice--systems to public health disease surveillance, there are a number of key principles:

1. Byproduct--no added work to gather data. Information is gathered purely as a byproduct of normal clinical activities.

2. Automated--electronic, rule-driven actions are reliable, fast (as it occurs, not days later).

3. Relevant--Focus on data most likely to be of value in evaluation of a disease report--laboratory results, patient complaint, temperature. We avoid the use of nonclinical information sources, such as billing data or massaged diagnosis codes.

4. Translation--We accept that each data provider will use idiosyncratic and unique codes. We accept data as they come, provide translation function centrally (we do not insist that hospitals or providers redo their systems in order to connect to public health).


For each pathology subspecialty, there is a different way we can support public health. For surgical pathology cytopathology, we make diagnoses of malignancy (that are used in tumor registries and other tools to track the incidence and deduce the causation of tumors) and other findings of public health importance. On occasion, findings that begin in the pathology research laboratory, such as the association of asbestos exposure with mesothelioma, of human papilloma virus with cervical cancer, of cigarette smoking with adenocarcinoma of lung, of hepatitis with liver cancer, or many other examples, assume great importance in guiding the public policy stance of the public health practitioner. One of the best examples is the automated transfer of tumor diagnoses from surgical pathology to the cancer registry. The first automated transfer of SNOMED-coded diagnoses from a surgical pathology information system to a cancer registry was implemented in 1977, (1,2) but the generalization of this capability to other surgical pathology information systems has only become more common in the past few years. (3) Since 2005, there have been 2 published versions of the North American Association of Central Cancer Registries standards for transfer of tumor information from surgical pathology information systems to central cancer registries. (4)

Forensic pathology identifies cases of infectious and toxic diseases highly significant to the public's health, as well as patterns of injury and violence addressed by the injury and violence prevention program of the public health agency. Coroner/medical examiner data are therefore very useful to public health. (5) At a minimum, it should alert our colleagues in public health to the occurrence or increasing incidence of serious (fatal) infectious diseases. By the same token, the medical examiner's findings can help track patterns of traumatic death--to determine epidemiology, potential intervention/prevention, and policy initiatives. The medical examiner also detects a diversity of other conditions. To make such surveillance most effective, we advocate direct electronic transmission of case reports from the coroner/medical examiner case management system to public health epidemiology systems. For example, Los Angeles County Public Health, California, has been receiving a daily transmission of coroner's cases since 2002.

Clinical pathology identifies infectious diseases, toxic exposures, and other disease patterns urging a public health response. Population patterns of antimicrobial susceptibilities track increasing rates of resistant bacteria. Tracking the number of test orders for selected sentinel tests, such as the number of blood cultures, may be indicative of an increased incidence of serious febrile illness (or other conditions of public health importance). At the same time, clinical pathology identifies many cases of public health-reportable disease via organism culture (Salmonella) and immunologic (hepatitis B) and nucleic acid-based (Chlamydia, Gonococci) techniques. Other tests, such as hemoglobin A1C, allow the assessment of diabetes burden in the population.

The domain of electronic laboratory reporting from clinical laboratory information systems to the public health infectious disease surveillance database is where there has been the most activity and connections made between pathology and public health. (6) National laboratories, local independent laboratories, public health laboratories, and hospital laboratories have been connected. In some settings, the laboratory information system (eg, Sunquest, Softlab [Clearwater, Florida], commercial laboratories, such as LabCorp [Burlington, North Carolina] and Quest [West Hills, California]) has the programming on board to automatically select, from all laboratory results, those that are reportable to public health. In most such cases, the software on the laboratory's laboratory information system (LIS) also includes translation tables to convert the laboratories' local/idiosyncratic test codes and organism codes to standard terminologies (Logical Observation Identifier Names and Codes [LOINC] (7-9) and SNOMED).

Other laboratory information system software (Meditech [Westwood, Massachusetts] Magic and Client Server, Cerner [Kansas City, Missouri] Classic and Millennium) lacks the filtering and translation capability. Interfaces from these systems typically call on the LIS to produce a total result output in Health Level 7 (HL7; Ann Arbor, Michigan) format. Filtering and translation must be provided by software running on an external system--typically more costly to implement and maintain.

In addition to traditional reportable diseases, public health is beginning to implement transfer of broad-range antimicrobial susceptibility testing (to enable evaluation of emerging trends in antimicrobial resistance (such as methicillin-resistant Staphylococcus aureus or vancomycin-resistant enterococci). Finally, some laboratories are providing to public health a complete picture of laboratory test orders--or even deidentified results--with the thought of evaluating syndromes based on a physician's ordering patterns and rates of abnormal results. (10)

Not only does electronic laboratory reporting greatly increase the reporting rate, but it provides more rapid transmittal of required reports, more complete reporting (we do not have to rely on the laboratorian's memory that a particular rare disease is reportable), savings in laboratory staff time, more accurate transmission (the risk of transcription and other errors is greatly reduced), and assured regulatory compliance. (11-22) Addressing this last point, the Health Insurance Portability and Accountability Act regulations require that a laboratory keep a log of all results sent to outside parties, including required reports to public health. The electronic laboratory reporting process automatically keeps such logs--likely more completely and accurately than any log kept by a manual-reporting laboratory.

To connect your laboratory to the electronic laboratory reporting system in your community, the primary step is to talk with members of your local public health department. Are they ready to receive data? What format/coding do they want? In the United States, we are moving toward standardization on HL7 version 2.5.1. However, the eventual answer to these questions is likely to be highly influenced by the capabilities of your own laboratory information system.


Talk with the vendor of your laboratory's LIS. What sort of public health module is available? How do we go about installing it? Is it a module that can only dump all results of the laboratory out through an HL7 interface? Is this HL7 dialect at least 2.3.1? Or something earlier? Or something nonstandard? Or does it provide the capability to select reportable cases and provide LOINC and SNOMED transformations before sending the HL7 transaction?

Does the LIS module match the specifications preferred by your local public health jurisdiction? As of this writing, Sunquest and SCC Soft (Clearwater, Florida) appear to provide the most extensive capability. Meditech and Cerner are capable only of sending an HL7 dump of all laboratory results. Although several LIS vendors claim to transmit laboratory data to public health, (23) we know relatively little about the capabilities of McKesson (Alpharetta, Georgia) Horizon/Star, Orchard (Carmel, Indiana), Aspyra (Calabasas, California), and other vendors.


There are multiple steps in the transformation of clinical data (Figure 1) from the source system until it is routed and usable in the appropriate public health jurisdiction--and to the proper program within that jurisdiction.

We gather a number of different types of health-related data into our public health database, both individual based (identified) and population based (deidentified): diagnoses of individuals, symptoms in populations, behavior of populations, as well as other data types (Figure 2).


1. Diagnoses of individual "reportable" diseases come to public health via fax, mail, manual entry, Web-based entry by providers, electronic laboratory reporting and, eventually, via automatic extraction from electronic medical records systems. These diagnosis records are used to build a longitudinal database in a jurisdiction's case management system. In Los Angeles County, California, we use a tool called vCMR (originally, this stood for visual Confidential Morbidity Report; however, we continue to use the acronym even though it was converted from Visual Basic to a fully Web-based user interface). vCMR was developed for us, and it is being enhanced and maintained by Atlas Development Corporation (Calabasas, California). The case management tool facilitates follow-up on cases by nurses, epidemiologists, and physicians.

2. Symptoms in populations are assessed from a number of data sources. The most important is the automated collection of emergency department (ED) chief complaint data. This is deidentified data, providing us only age, sex, and ZIP code of residence. In Los Angeles County, more than 35 such connections enable us to study symptom patterns encompassing more than 55% of ED visits each day. Figure 3 shows that patients living in almost all regions of the county are likely to visit an ED covered by this system (the major red--"uncovered"--areas are sparsely populated and mountainous). These data come to us within 24 hours of the visit, enabling a very rapid assessment of real-time population health. The system parses the free text chief complaints, classifying them into syndromes, and looks for patterns and deviations from historic norms. Similar systems have been found useful in other jurisdictions. (24-26) A second system brings us data on patient concerns expressed in calls to a network of nurse-call phone lines. More detail on the ED chief complaint system is provided later in this paper.

3. A third type of data source is to examine behavior of populations. We daily review information on purchases of over-the-counter medications (provided to us in a database assembled and maintained by the University of Pittsburgh (Pittsburgh, Pennsylvania) Real-Time Outbreak and Disease Surveillance Laboratory). A spike in the purchase of fever thermometers would be suggestive of an outbreak of febrile illness; an increase in antidiarrheal purchases would suggest an agent causing diarrhea. In general, we use the medication data (Figure 4) as a supplement to the ED chief complaint indicators.

4. Other sources: Many public pealth agencies regularly receive data on ambulance services (we began receiving such data in mid-2008). We receive another data stream about ED visits--a global daily count of cases, admits, admits to the intensive care unit, and deaths; we receive this data from almost all EDs in the county--in addition, we can as needed add specific questions to address emergent issues.

5. In addition to the above--current reality--data sources, clinical systems are becoming more sophisticated. As highly capable systems become more widely deployed, greater quality and detail of data can be transferred to public health. As EDs install complete records systems, several data elements in such systems will be relevant and useful to evaluating the public health significance of cases. Likewise, ambulatory electronic health records (27) with discrete fielded/codified data (as opposed to blocks of free text or--even worse--scanned images of illegible physician's notes) will be a rich source for automated reporting of cases to public health. Granular hospital systems, such as intensive care unit systems, will be equally useful. In each such case, rather than imposing on the clinician to remember that such an instance constitutes a reportable case, automatic rules can recognize them, notify the clinician that a report is being made, and automatically transfer the information to public health.




Pathologists and their knowledge of informatics have played a crucial role in construction of the extensive disease surveillance network described above. A diverse and detailed data collection system is a crucial component of our defense against natural and manmade (bioterrorist) epidemics.


In building systems for bioterrorism preparedness, we now recognize that we have created a real-time population health surveillance system. The major improvement in usefulness of this system has been achieved via coordination of data feeds through a robust, secure, accessible data center.

As described above, in Los Angeles County the number of EDs reporting has steadily increased. The system started in 2000, and by late 2005 it had grown to 9. This grew to 17 in July 2006 and to 28 by July 2007, and as of June 2008 we received daily reports from 36 EDs. The data are received and analyzed 7 days per week, and a daily summary/interpretive report is sent to approximately 75 public health staff and hospital partners. (28-30) The system also monitors various aspects of health status and allows us to perform case finding and health assessment--for example, the impact of the summer heat wave, or assessing the flu season (Figure 5).


Presenting complaints are automatically categorized into a particular syndrome by word search. Over the past several years, from the literature and, more recently, from our own local experience, the analytic team has built lists of key words that are commonly correlated with syndromes of interest. The SAS-based analytic software compares each chief complaint with these lists and determines whether the key words are found to group it into a respiratory, gastrointestinal, neurologic, or rash syndrome. During the summer, heat-related words are examined for categorization into that syndrome. Influenza-like illness syndrome (Figure 5) is defined by a subset of the words used for the general respiratory category. We are considering adding additional syndromes, such as trauma. Thus, a single case can be classified into more than one syndrome grouping. If none of the key words are found, the case is categorized as "other" and not further examined. Syndrome counts are tracked over time. A statistic increase in count of any syndrome triggers a signal--the analyst reviews the individual line listing, assesses whether they appear to have similarities (or are just a coincidental cluster), and refers suspicious clusters to the physician on call, and then on to the hospital outreach team nurses (a unit of our public health acute communicable disease control program). The objective of this syndromic review is to detect major trends from baseline patterns, NOT individual cases.


Pathologists and other laboratorians have a valuable skill set. Much pathology training also prepares one for public health. It is not necessary to have specialized public health training to make a worthwhile contribution to public health. If a laboratorian decides that he or she would like to contribute, how does he or she go about doing that? There are opportunities on contract, or salary arrangements. For example, some pathologists (and many clinical laboratorians) serve as directors of public health laboratories. Most pathology practices have some involvement with hospital infection control; some laboratorians have pursued that to full-time commitment in public health epidemiology. The informatics skills we have developed in pathology/laboratory medicine are badly needed in public health. In a few jurisdictions, pathologists have become the health officer (the principal public health official for a jurisdiction). One can also volunteer one's services in public health. This is particularly needed in resource-poor countries.


Pathologists and other laboratorians have an important role in ensuring the public's health. We can provide valuable data from our roles in both anatomic (surgical and forensic) and clinical pathology. Electronic connections between pathology information systems and public health systems are complex, but they yield many benefits in more rapid and accurate information to benefit the health of the population. Our roles in our health care organizations position us well to encourage connection of other clinical systems (EDs, electronic medical records) to the public health disease surveillance system. In addition to the value of facilitating these connections, pathologists and other laboratorians have skill sets valuable to direct application in public health--both within the United States and in resource-poor countries around the world.

Financial support was provided by the Centers for Disease Control Cooperative Agreement for Bioterrorism and Emergency Preparedness and Response.


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Accepted for publication January 6, 2009.

From the Automated Disease Surveillance Section, Acute Communicable Disease Control Program, Los Angeles County Department of Public Health, Los Angeles, California.

Presented in part at the First World Congress On Pathology Informatics, Brisbane, Australia, August 1 7, 2007.

The author has no relevant financial interest in the products or companies described in this article.

Reprints: Raymond D. Aller, MD, PO Box 2168, Vista, CA 92085 (e-mail:
Gale Copyright: Copyright 2009 Gale, Cengage Learning. All rights reserved.