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Data Development and Use

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Researchers describe use of large databases to measure outcomes of care

The Sixth Regenstrief Conference, "Measuring Quality, Outcomes, and Cost of Care Using Large Databases," was held September 4-6, 1996, in Marshall, IN, and was supported in part by a conference grant (HS09345) from the Agency for Health Care Policy and Research. The conference highlighted several success stories from users of large clinical databases, as well as some cautionary tales by experienced users of various databases. Experts spoke on issues ranging from uses of specific databases, measurement of outcomes, and measurement of the process and cost of care to establishing linkages among databases, biostatistical issues in database research, report card and profiling practices, and the future of databases and research.

Four papers presented at the conference were supported by the Agency for Health Care Policy and Research and are briefly summarized here.

Christiansen, C.L., and Morris, C.N. (1997, October). "Improving the statistical approach to health care provider profiling." (AHCPR grant HS07118). Annals of Internal Medicine 127, pp. 764-768.

The authors review and compare existing statistical methods for profiling health care providers. They recommend improvements that are based on the use of better statistical models and the adoption of more realistic, medically based criteria for judging the performance of providers. The researchers propose hierarchical models that can extract more information from profiling data. Such models would be able to answer such questions as, "What is the probability that a given hospital's true mortality rate for cardiac surgery patients exceeded 3.33 percent last year?"

Matchar, D.B., Samsa, G.P., Matthews, R., and others (1997, October). "The stroke prevention policy model: Linking evidence and clinical decisions." (AHCPR PORT contract 290-91-0028). Annals of Internal Medicine 127, pp. 704-711.

The Stroke Prevention Patient Outcomes Research Team (PORT) presented their study on the Stroke Prevention Policy Model (SPPM) that synthesizes information on stroke from several sources into a single comprehensive structure. The paper describes the basic structure and functions of the SPPM, the role of large databases in providing the SPPM inputs, and controversies surrounding the use of modeling.

By linking a model of the natural history of the disease (as possibly modified by information about interventions) with patient preference and cost models, the SPPM can be used to evaluate the cost-effectiveness of various intervention strategies. The researchers conclude that the benefits of such models to support clinical decisionmaking more than outweigh the costs of continuing to rely on more conventional methods.

McDonald, C.J., Overhage, J.M., Dexter, P., and others (1997, October). "A framework for capturing clinical data sets from computerized sources." (AHCPR grant HS07719). Annals of Internal Medicine 127, pp. 675-682.

Today much electronic patient information is available in operational data systems (for example, laboratory systems, pharmacy systems, and surgical scheduling systems) and is accessible by agencies and organizations through standards for messages, codes, and encrypted electronic mail. According to these authors, a framework is needed to capture clinical data sets from computerized sources. Agencies and organizations should define the elements of their data sets in terms of standardized operational data, and data producers should fully adopt these code and message standards.

Ray, W.A. (1997, October). "Policy and program analysis using administrative databases." (AHCPR grant HS07768). Annals of Internal Medicine 127, pp. 712-718.

Administrative policies and programs play an important and growing role in determining the use of medical care. Although some administrative policies and programs may be harmful or ineffectual, randomized, controlled trials or prospective evaluations of them are rarely done. Most evaluations are retrospective and often use administrative databases. Major problems with such evaluations include poor data quality, lack of concurrent controls, inability to ascertain important study outcomes, and incomplete data on case mix. The author of this article uses published evaluations to illustrate these problems and suggests strategies that can minimize their impact.

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AHCPR News and Notes

From the Administrator: Purchasers look to health services research for the information they need in today's market-driven health care arena

A basic principle of market-driven health care is that it provides purchasers with the opportunity for informed choices. The challenge to health services researchers is to make this information-based health care market approach work as well as possible. We can do this by providing the information and tools that all the stakeholders—patients, providers, purchasers, health plan administrators, and policymakers—need to make informed decisions, measure and monitor quality, and seek value for the money they spend on health care services, says John M. Eisenberg, M.D., Administrator of the Agency for Health Care Policy and Research.

As Dr. Eisenberg points out in a recent commentary, providing information for health care decisionmaking is at the core of AHCPR's mission. The Agency supports the outcomes research that helps clinicians and consumers make decisions about which tests and treatments to use for which patients and at which point in the course of their illness. AHCPR provides science-based information about the organization and financing of health care services to assist health plans, purchasers, health care institutions (such as hospitals), and government officials in making important management decisions. Finally, AHCPR researchers develop the tools and products that help States and the Federal Government fulfill their responsibility to monitor and improve health care quality.

Dr. Eisenberg's first priority as administrator of AHCPR, the lead agency charged with improving the quality of health care services in the United States, is to maintain the level of excellence of the research AHCPR supports and conducts, and to raise it where possible. His second priority is to foster innovation and creativity from the "best and the brightest" in health services research. The Agency will seek out partnerships and collaborations with public and private sector organizations to share in the funding of targeted research. Another priority is to see that health services research leads to action at all levels of health care decisionmaking, from the examination room to the management suite to the public policy arena.

For more details, see "Views from funding agencies: Agency for Health Care Policy and Research," by Dr. Eisenberg, in Medical Care 36(1), pp. 6-7, 1998. Reprints (AHCPR Publication No. 98-R015) are available from the AHCPR Publications Clearinghouse.

AHCPR encourages researchers to submit applications

The Agency for Health Care Policy and Research recently issued an ongoing program announcement that expresses the Agency's priority interests in extramural research, demonstration, dissemination, and evaluation projects. This program announcement sets forth the Agency's research agenda, which is designed to be responsive to the needs of consumers, patients, clinicians and other providers, institutions, plans, purchasers, and Federal and State policymakers for evidence-based information that can be used in efforts to improve quality and outcomes, control costs, and assure access to needed services.

The FY 1999 budget request for AHCPR is $171 million, an increase of $25 million, or 17 percent, over the FY 1998 level. Most of this amount is intended to support investigator-initiated research to improve health outcomes and strengthen quality measurement and quality improvement, including research on the organizational and financial aspects of health care.

As described in the program announcement, AHCPR is also interested in applications for projects that will identify strategies to improve access, foster appropriate use, and reduce unnecessary expenditures—including the use of evidence-based practice information and tools, as well as for studies on the characteristics of primary care practice.

Three over-arching priority areas are identified in the program announcement:

  1. Support improvements in health outcomes. Drawing from the literature on variations in clinical practice, the documented increase in occurrence of chronic diseases, and growing interest in the impact of different delivery modalities and financing arrangements on the outcomes of care, AHCPR is interested in research to better understand and improve the outcomes of health care and, in particular, what works, for whom, when, and at what cost.
  2. Strengthen quality measurement and improvement. This includes a broad array of research topics, ranging from studies to develop valid and reliable measures of the process and outcomes of care, to strategies for incorporating quality measures into programs of quality improvement, to understanding the influence of organizational as well as clinical factors on levels of quality, to dissemination and implementation of validated quality improvement mechanisms to test their generalizability and examine alternative ways to collect, compare, and report the resulting information.
  3. Identify strategies to improve access, foster appropriate use, and reduce unnecessary expenditures. This area focuses on issues pertaining to the types of health care services Americans use, the costs of these services, and sources of payment; determinants of access to care; and whether particular approaches to health care delivery and financing or characteristics of the health care market alter behaviors in ways that improve access and promote the cost-effective use of health care resources.

Two additional areas, which are becoming increasingly important in today's market-driven health care delivery system, also deserve attention. These are research on methodologic advances in health services research, especially cost-effectiveness analysis, and research on ethical issues across the spectrum of health care delivery.

For each of the priority areas, applicants are encouraged to address health issues related to special populations, including minorities, women, and children.

AHCPR encourages research using data from the Medical Expenditure Panel Survey (MEPS), developed by AHCPR in collaboration with the National Center for Health Statistics, and other AHCPR-supported data bases such as the Healthcare Cost and Utilization Project (HCUP-3).

The Agency also encourages partnerships with private and public organizations to facilitate development and sharing of scientific knowledge and resources, including cost-sharing mechanisms; projects that will produce results within 2 to 3 years; and results that can be integrated rapidly into practice or policy.

The new program announcement also applies to applications for AHCPR grants for small projects, dissertation support, large and small conference grants, and training support. The announcement is ongoing, meaning applicants can submit proposals at the standard receipt dates for Public Health Service research grants, which are February 1, June 1, and October 1. This contrasts with requests for applications (RFAs) which have set receipt dates and focus on selected research issues.

Although this program announcement covers a broad range of issues, AHCPR will consider applications for research on other subjects, so long as they contribute to the Agency's goals and fall within its scope of interests.

Full details, including the names of agency staff members who can be contacted for further information, are in AHCPR Health Services Research—Program Announcement (AHCPR Publication No. 98-0018), which is available online. Application materials are available from the NIH Grants Web Site.

This program announcement (PA-98-049) was published March 26, 1998, in the NIH Guide to Grants and Contracts.

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AHCPR, CDC, AAHP, and the HMO Research Network to host the fourth annual "Building Bridges" conference

The Agency for Health Care Policy and Research and the American Association of Health Plans (AAHP), the HMO Research Network, and the Centers for Disease Control and Prevention will host "Building Bridges IV: Improving the Public's Health Through Research Partnerships" May 7-9, 1998, at the Oakland Marriott City Center, Oakland, CA.

Conference participants will have an opportunity to exchange views with leaders in the health services research and managed care communities on issues such as:

  • The need for health plans to be involved in both health services and clinical research.
  • The ways health plans are able to impact both public health and the health of their members through research partnerships.
  • Techniques health plans can use to develop collaborative research arrangements with both public and private partners.

Four plenary sessions—two each day—will be featured and will focus on children and managed care, confidentiality of health data, medical and ethical implications of advances in genetics, and continuous improvements in health. Speakers include AHCPR Administrator John M. Eisenberg, M.D., and Deputy Administrator Lisa Simpson, M.B., B.Ch., Andy Nelson, M.P.H., Executive Director of the Group Health Foundation, Mark Smith, M.D., M.B.A., President of the California Healthcare Foundation, and James Perrin, M.D., Associate Professor of Pediatrics, Howard Medical School. William McGuire, M.D., President and CEO of United Healthcare Corporation, has been invited to give the keynote presentation that opens the conference.

A wide range of nonrepeating concurrent sessions will be held, including sessions that focus on new models of care for chronic illness, employer issues, conducting clinical trials in health plans, breast cancer treatment and prevention, maternal and child health, the impact of guidelines on clinical practice, mental health/substance abuse, and many other topics.

Conference attendees will include health services researchers, policymakers, public health professionals, care managers, medical directors, managed care CEOs, quality improvement professionals, academicians, information systems specialists, and others who are interested in improving research on managed care issues by enhancing communication and collaboration among researchers, medical groups, and health plans.

The conference registration deadline is April 13; after that date, registrations will be accepted on a space-available basis. For more information, contact Jill Arent at AAHP, 1129 20th Street, N.W., Suite 600, Washington, DC 20036-3421; phone (202) 778-3234; fax (202) 778-3421; E-mail

Registry of State-level efforts to integrate health data can be found on the Internet

The U.S. Department of Health and Human Services (HHS) has developed an Internet registry of State data integration efforts, which includes information on related State data policy activities and the names of contact people for each State. Daniel Mendelson, Vice President of the Lewin Group, described the registry at a recent Agency for Health Care Policy and Research User Liaison Program (ULP) workshop held for State and local health policymakers.

The Lewin Group updated the registry under a HHS contract. The registry, which can be found at, serves as a clearinghouse of information that (1) identifies States that have pursued information integration activities, (2) facilitates information sharing and collaboration, and (3) assists policymakers and others in monitoring, assessing, and supporting State-level data integration activities.

The registry uses a broad definition of "data integration" in identifying relevant State projects, including everything from community profiling systems that draw data from different sources, to hospital discharge datasets that collect information across providers, to real-time management information systems. All 50 States are included, as well as a taxonomy that describes the States' activities. Users can search the registry by a particular State, or they can do a keyword search.

For more information about integrated State health information systems, select an online workshop summary.

AHCPR's ULP is responsible for disseminating health services research and other health-related information to State and local health policymakers. ULP accomplishes its mission primarily by sponsoring workshops on issues of immediate importance. In 1997, for example, State oversight of integrated delivery systems, caring for the uninsured, and providing high-quality services to children with disabilities were among the areas discussed.

New report describes ways to evaluate performance, improve patient care, and operate more efficiently

What do Kaiser's On-the-Job program in Portland, OR, Minneapolis' Pediatric Asthma Care Initiative, and the Denver-based Primary Care Physician Direct Referral Pilot Program have in common? They are innovative projects operated by managed care organizations that are designed to meet the growing demand for more patient-centered care processes, improved service to consumers and purchasers, and better documentation and reporting of performance.

Known as organized systems of care, these providers integrate financing and health care delivery and are held clinically and fiscally accountable for the outcomes and health status of the patients they serve. Their pioneering activities are the subject of a new 165-page case study report by the Washington Business Group on Health (WBGH), Managing Care, Operations and Performance: Innovations in Organized Systems of Care. The Agency for Health Care Policy and Research funded the research for the report.

The 12 innovations described in the report—from new approaches to providing patient care to exciting new uses of information technology—will provide important benchmarks for both public and private sector purchasers of health care and educate policymakers about how managed care systems respond to the pressures and demands of a competitive marketplace. The programs are operated by: Allina Health System, Group Health Cooperative of Puget Sound, Harvard Pilgrim Health Care and Digital Equipment Corporation, Henry Ford Health System, Kaiser Permanente Northwest, Lovelace Health Systems, Merit Behavioral Care Corporation/Pacificare, MacGregor Medical Association/Prudential HealthCare, United HealthCare, Colorado Permanente Medical Group and Kaiser Foundation Health Plan, and Dean Health Systems, Inc.

Select for an online summary of the report. A limited number of free copies of the printed report (AHCPR Publication No. OM-98-0006) are available from the AHCPR Publications Clearinghouse.

In addition, single and multiple copies of the report, as well as individual case studies, are available from the Washington Business Group on Health. For price and other information, contact Ann Makowski, WBGH, 777 N. Capitol Street, Suite 800, Washington, DC 20002; phone (202) 408-9320; fax (202) 408-9332; e-mail

NMES data now available on a single CD-ROM

For the first time, data from all files from the 1987 National Medical Expenditure Survey (NMES) Household Survey and Health Insurance Plans Survey have been released by the Agency for Health Care Policy and Research on a single CD-ROM. These data were previously released by AHCPR as EBCDIC files and are being re-released as ASCII files for use on microcomputers.

A documentation file including codebook(s) and a file containing programming statements for SAS users are included on the CD-ROM for use with each of the data files. Some of the documentation files are in portable document format (PDF) for which Adobe® Acrobat® Reader™ software is also provided on the same CD-ROM.

Data from the following NMES Public Use releases are included on this CD-ROM:

  • Public Use File 9, Household Survey, Health Status Questionnaires and Access to Care Supplement Data.
  • Public Use File 10, Household Survey, Long-Term Care Supplement Data.
  • Public Use File 13, Household Survey, Population Characteristics and Utilization Data for 1987.
  • Public Use File 14.1, Household Survey, Prescribed Medicine Data, Calendar Year 1987.
  • Public Use File 14.2, Household Survey, Home Health Care and Medical Equipment Purchases and Rentals Data, Calendar Year 1987.
  • Public Use File 14.3, Household Survey, Dental Visit Data, Calendar Year 1987.
  • Public Use File 14.4, Household Survey, Hospital Stays Data, Calendar Year 1987.
  • Public Use File 14.5, Household Survey, Ambulatory Medical Visit Data, Calendar Year 1987.
  • Public Use File 15, Health Insurance Plans Survey, Policyholders of Private Health Insurance—Premiums, Payment Sources, and Type and Source of Coverage.
  • Public Use File 18, Household Survey, Expenditures, Sources of Payment, and Population Data for 1987.
  • Public Use File 29, Household Survey, Disability Days, and Medical Conditions, Calendar Year 1987.
  • Public Use File 31R, Household Survey, Data from the Care-Giver and Care-Receiver Supplements.
  • Public Use File 34R, Household Survey, 1987 Jobs File and Link to Employment-Related Insurance Coverage.
  • Public Use File 40R, Data from the Household Survey, the Health Insurance Plans Survey (HIPS), the Survey of American Indians and Alaska Natives (SAIAN), and the Institutional Population Component (IPC). (This CD-ROM contains only these data from release 40R: data on all health insurance plans offered by potential employment-related sources—i.e., held plans and optional plans—from the HIPS; summarized benefits data and actuarial values from the HIPS for linked policyholders and dependents; and death certificate data for people in the Household Survey and the IPC or the SAIAN).

The CD-ROM, Data from the 1987 NMES Household Survey and Health Insurance Plans Survey (AHCPR Data Product No. 98-DP02), is available from the AHCPR Publication Clearinghouse.

For more information about the data releases call Kelly Carper at the Center for Cost and Financing Studies, AHCPR, (301) 427-1656.

Calling all AHCPR Web site users

We want to hear from you. Customer feedback from users the the AHCPR Web site will help us make it responsive to your needs and the needs of other users.

AHCPR is conducting an online survey, and we want you to tell us how we are doing and what we could do better. AHCPR's Web site offers access to information and data related to the Agency's activities in the areas of health services research, quality measurement and improvement, clinical care, health technology assessment, and medical expenditures. The site also features consumer information for health care decisionmaking.

Please take a few moments and select the Web Evaluation Form. Rate us on design, content, and usefulness. Your ideas are invited on how we can make this electronic dissemination system more responsive to your information needs.

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Research Briefs

Diehl, M., Spore, D.L., and Smyer, M.A. (1997, December). "Measurement properties of the short multidimensional observation scale for elderly subjects (MOSES)." (NRSA training grant T32 HS00011). Journal of Applied Gerontology 16(4), pp. 403-426.

Proper assessment of the functional status of nursing home residents is important for issues such as resident screening, placement decisions, care plan development, and monitoring of resident status over time. But most multidimensional assessment instruments have been designed for use by specially trained professionals such as geriatric nurses or psychologists. This study shows the practical value of a short five-factor model of the Multidimensional Observation Scale for Elderly Subjects (MOSES). It was used to evaluate the functional status of 273 nursing home residents from 4 Pennsylvania nursing homes. Nursing assistants were able to complete the instrument with little difficulty. The items contained in the short MOSES appeared to be sufficiently concrete and behavior-specific that nursing assistants could provide reliable accounts of the residents' functioning in the relevant domains. Reliabilities were particularly good for easily observable behaviors such as self-care activities and disorientation, and somewhat lower for behaviors indicative of depression, irritability, and withdrawal.

Friedman, R.H., Stollerman, J.E., Mahoney, D.M., and Rozenblyum, L. (1997, December). "The virtual visit: Using telecommunications technology to take care of patients." (AHCPR grant HS05135). Journal of the American Medical Informatics Association 4(6), pp. 413-425.

Telephone-linked care (TLC) technology is in use at Boston Medical Center as an adjunct to office visits. The patient simply picks up his or her home phone and dials TLC, which consists of a computer-controlled digitized human voice and database components. Patients use their telephone key pad or talk into the receiver to communicate. TLC conversations generally last 2 to 15 minutes per call and take place weekly for periods of at least 3 months for patients with chronic disease. For example, in TLC-Hypertension, patients monitor their blood pressure weekly and report the values to TLC. TLC, in turn, provides the patient's clinician with the blood pressure information, displayed in graphic format. TLC for chronic diseases typically asks a patient questions that assess disease status. TLC asks patients about key symptoms of the disease being monitored, their level of activity during the week, and what, if anything, stopped them from doing an activity. TLC also gives advice in response to information given by the patient. Depending on the urgency of the information gathered by the TLC, the clinician will receive it on alert reports sent immediately (electronically or by fax) or on standard monthly reports. Patient reports are placed in the patient's paper or electronic medical record. TLC clinical applications being developed include changing lifestyle behaviors such as diet, smoking, and physical activity.

Halamka, J.D., Szolovits, P., Rind, D., and Saffron, C. (1997, December). "A WWW implementation of national recommendations for protecting electronic health information." (AHCPR/National Library of Medicine Interagency Agreement). Journal of the American Medical Informatics Association 4(6), pp. 458-464.

Connecting every hospital to the Internet so that doctors can instantly share data about their patients with the best specialists in the field is a goal that has been impeded by concerns about security and confidentiality. But the Web-based, CareWeb cross-institutional medical record system developed by Beth Israel Deaconess Medical Center in Boston, MA, appears to have solved some of these problems. One of the chief concerns in such a system is making sure that only authorized persons access a patient's health record and that all patient-identified data transmitted over public networks is encrypted so that others can't "read" it. This must be done in a way that does not impede quick access by the physician who needs it. CareWeb's software architecture includes use of hardware tokens such as smartcards, magnetic strip IDs, or devices with constantly changing passwords to authenticate users; use of cryptographic methods to protect information flow over public networks; and creation of a multiorganizational auditing system that allows retrievable audit trails that log time, date, information accessed, and user ID for all information accessed. During initial testing of the prototype system, the Web site processed 3,000 requests for health care information and found neither unauthorized access nor inappropriate denial of access to the site. Twenty-five health care providers who evaluated the system gave it high marks in ease of use, response time, and usefulness in patient care.

Heymann, S.J., Brewer, T.F., and Ettling, M. (1997, December). "Effectiveness and cost of rapid and conventional laboratory methods for Mycobacterium tuberculosis screening." (NRSA fellowship F32 HS00079). Public Health Reports 112, pp. 513-523.

Newer rapid methods of diagnosing tuberculosis (TB) and testing TB bacteria for drug susceptibility are more cost effective than slower traditional approaches, concludes this study. The researchers used decision analysis to compare newer rapid and older nonrapid methods for diagnosing TB and testing for drug susceptibility. Results showed that using a combination of solid medium and broth, cultures, nucleic acid probes for identification, and radiometric broth drug susceptibility testing would lead to diagnosis an average of 15 days faster and to appropriate therapy an average of 5 days sooner than methods currently employed by many U.S. laboratories. The average mortality would drop by .5 percent (5 per 1,000 patients) evaluated (31 percent), and the average cost per patient would drop by $272 (18 percent), calculate the researchers. They conclude that U.S. laboratories should employ available rapid techniques for the diagnosis of TB.

Hogan, A.J. (1997). "Methodological issues in linking costs and health outcomes in research on differing care delivery systems." Medical Care 35(11), pp. NS96-NS105.

This article discusses, from an economist's point of view, issues in designing and conducting research, including cost and outcomes variables, among differing care delivery systems. Such research is difficult even when one excludes from consideration "pure" technological changes (new devices, drugs, or procedures that replace older ones in the same care delivery system) and "pure" price changes (changes in prices charged for essentially equivalent services resulting from changes in ownership or insurance coverage). The author reviewed research purporting to link cost and outcomes with variations in care delivery systems. He found that current literature on nursing care delivery systems and costs in hospitals, ambulatory care settings, and nursing homes is focused mainly on group-specific costs linked to patient-specific outcomes. It suffers further from focusing primarily on single-discipline components of care, omitting the contributions of other providers beyond nursing personnel.

Russell, L.B., Milan, E., and Jagannathan, R. (1997). "Comparison of two surveys of hospitalizations." (HS07002). Vital Health Statistics 2(123), pp. 1-16.

In this report, the authors compare hospitalization data from the National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Followup Study (NHEFS) with data from the National Hospital Discharge Survey (NHDS), the benchmark for hospitalization in the United States, for men and women 35 years and older for the period 1971 to 1987. The comparison is intended to help analysts evaluate the validity and generality of analyses based on the NHEFS. The comparison showed that hospital stays per 1,000 population were lower in NHEFS than in NHDS in all age-sex groups at the beginning of the period, but the differences had almost disappeared by 1987. Lengths of stay, although somewhat longer in NHEFS, matched NHDS more closely. Differences by age and sex were similar in the two surveys for both hospital stays per 1,000 population and length of hospital stay. This evaluation suggests two points for researchers who want to use the NHEFS. First, including age as a control should largely correct for differences in age distribution between the two surveys. Second, a time trend should also be included to capture the effects of several factors that caused the count of stays to be low in the early years of NHEFS followup.

Strickland, G.T., Karp, A.C., Mathews, A., and Pena, C.A. (1997). "Utilization and cost of serologic tests for Lyme disease in Maryland." (AHCPR grant HS07813). Journal of Infectious Diseases 176, pp. 819-821.

Lyme disease (LD) is the most common vector-borne illness in the United States and is increasing in prevalence and distribution. The hallmark of early infection, a bull's-eye-shaped (erythema migrans, EM) rash, is absent in 30 to 40 percent of patients meeting the case definition for LD. In acute cases in which EM is not present, and in patients with more chronic complaints, serologic testing is relied upon to support the diagnosis. These researchers surveyed all laboratories registered with the Maryland State Health Department to ascertain the use of serologic tests for LD in the State. Results show that from 1992 to 1995, 17 laboratories performed 100,000 serologic tests costing $7.1 million on Maryland residents; 90 percent of these tests were EIAs, the most commonly performed test. The proportion of positive EIAs increased from 3.4 percent in 1992 to about 7 percent in 1994 and 1995. The percentage of positive second tests (Western blot, WB) fell from 7.9 percent to about 5 percent. The large number of EIAs performed compared with the low incidence of LD in the State results in a low predictive value of a positive EIA test. Therefore, the WB is indicated to confirm both equivocal and positive EIA tests when characteristic clinical findings of LD are not present.

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AHCPR Publication No. 98-0019
Current as of March 1998

The information on this page is archived and provided for reference purposes only.


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