Study finds inappropriate laboratory testing throughout medicine
Laboratory testing is health care’s single highest volume activity, with more than 5 billion tests performed each year in the U.S.
A new study examining 15 years’ worth of published research reveals some surprising findings about blood tests.
Led by investigators at Harvard Medical School and Beth Israel Deaconess Medical Center and reported online in the journal PLOS ONE, the large-scale analysis of 1.6 million results from 46 of medicine’s 50 most commonly ordered lab tests found that, on average, 30 percent of all tests are probably unnecessary.
Even more surprising, the results suggest that equally as many necessary tests may be going unordered.
“Lab tests are used in all medical specialties, affecting virtually all patients,” said senior author Ramy Arnaout, HMS assistant professor of pathology and associate director of the clinical microbiology laboratories in the Department of Pathology at Beth Israel Deaconess.
“While working with my clinical colleagues around the hospital, I often found myself wondering about the appropriateness or inappropriateness of all of these tests. In developing this study, my coauthors and I wanted to learn more about overall lab test utilization so that we could better understand how and where errors were occurring in this extremely high-volume activity,” Arnaout said.
Their findings revealed a stark problem: Not only was there a 30 percent overall rate of test overuse, there was a similar rate of underuse.
While the authors found both overuse and underuse to be prevalent problems throughout laboratory testing, the overall findings point to a bigger issue, said Arnaout.
“It’s not ordering more tests or fewer tests that we should be aiming for, it’s ordering the right tests, however few or many that is,” he noted.
“Remember, lab tests are inexpensive. Ordering one more test or one less test isn’t going to ‘bend the curve,’ even if we do it across the board. It’s everything that happens next—the downstream visits, the surgeries, the hospital stays—that matters to patients and to the economy and should matter to us,” Arnaout said.
“This paper explores many of the nuances surrounding exactly how, when and why lab tests are ordered and misordered,” said Jeffrey Saffitz, HMS Mallinckrodt Professor of Pathology and chairman of pathology at Beth Israel Deaconess.
“Many times, the reasons for ordering tests seems to be based on dogma, the way it’s always been done. This comprehensive and meticulous analysis shows that there are patterns in laboratory test utilization that can reveal when we do a good job at ordering tests and where we need to do better,” Saffitz said.
To conduct the study, the authors undertook a thorough review of the medical literature. Going back to 1997—the year that the last previous review of lab tests had been conducted—Arnaout, together with first author Ming Zhi, an intern at Kaiser Permanente Santa Clara Medical Center, began by scouring a host of databases matching terms such as “laboratory,” “blood test,” “utilization,” “overuse,” and “underuse.” They came up with approximately 34,000 papers.
“We cast a wide net, then filtered things out and eventually got down to a couple of hundred papers on laboratory utilization,” said Arnaout.
Further refinement led to an examination of 42 papers covering 1.6 million orders of 46 of the 50 most commonly ordered lab tests. These ranged from common tests such as complete blood counts and basic metabolic panels to less common tests such as D-dimer (for pulmonary embolism) and HIV-1 tests.
From these measurements, they set about estimating the overall prevalence of inappropriate testing, including overuse (tests that are ordered but not indicated) and underuse (tests that are indicated but not ordered).
They also distinguished between inappropriate initial testing—during a clinician’s first evaluation of a patient or in response to new signs or symptoms—and inappropriate repeat testing, which occurs when the same tests are repeated—often multiple times—during a patient’s hospitalization.
“Most of the time when doctors talk about inappropriate lab testing, there’s a generally accepted notion that it’s too many ‘repeat’ tests being ordered,” said Arnaout.
“But, unexpectedly, on a per-test basis, we actually found that the main problem was tests being over-ordered during a patient’s initial examination, rather than during repeat tests. This indicates to us that ordering the right test during the initial evaluation may lead to fewer errors and better patient care,” he said.
The authors also established criteria that influence how doctors order lab tests and examined their final outcomes in the context of these criteria, for example, what they call restrictive vs. permissive criteria.
“In medicine, as a rule, we only do things if there is a reason,” said Arnaout. “You’d never have a situation where you drop a loved one off at the doctor and when you pick them up at the end of a day, they’re missing a foot because the doctor went down a checklist and couldn’t see any reason not to remove the foot. That doesn’t happen because medicine adheres to ‘restrictive’ policies. However, as our findings showed, laboratory medicine is the exception to this rule. In ordering blood tests, we too often tend to be permissive, asking ‘why not?’ instead of ‘why?’”
“These findings offer the field of pathology both an opportunity and challenge for the future,” added Saffitz.
“When it comes to appropriate lab testing, I think the pathologist has as much responsibility to get it right as the doctor who is ordering the test. This paper focuses attention on this important issue,” he said.
By BONNIE PRESCOTT
About Harvard Medical School (HMS)
Driving Change. Building Momentum. Making History.
“Since 1872, Harvard Medical School has been the incubator of bold ideas—a place where extraordinary people advance education, science and health care with unrelenting passion.
Whether training tomorrow’s doctors and scientists, decoding the fundamental nature of life, advancing patient care or improving health delivery systems around the world, we are never at rest. Allied with some of the world’s best hospitals, research institutes and a University synonymous with excellence, the School’s mission remains as ambitious as it is honorable: to alleviate human suffering caused by disease.”
About Harvard School of Public Health (HSPH)
Harvard School of Public Health is dedicated to advancing the public’s health through learning, discovery and communication. More than 400 faculty members are engaged in teaching and training the 1,000-plus student body in a broad spectrum of disciplines crucial to the health and well being of individuals and populations around the world. Programs and projects range from the molecular biology of AIDS vaccines to the epidemiology of cancer; from risk analysis to violence prevention; from maternal and children’s health to quality of care measurement; from health care management to international health and human rights.
About Harvard University.
Established in 1636, Harvard is the oldest institution of higher education in the United States. The University, which is based in Cambridge and Boston, Massachusetts, has an enrollment of over 20,000 degree candidates, including undergraduate, graduate, and professional students. Harvard has more than 360,000 alumni around the world.
Harvard University is devoted to excellence in teaching, learning, and research, and to developing leaders in many disciplines who make a difference globally. Harvard faculty are engaged with teaching and research to push the boundaries of human knowledge. For students who are excited to investigate the biggest issues of the 21st century, Harvard offers an unparalleled student experience and a generous financial aid program, with over $160 million awarded to more than 60% of our undergraduate students. The University has twelve degree-granting Schools in addition to the Radcliffe Institute for Advanced Study, offering a truly global education.
‘Universities nurture the hopes of the world: in solving challenges that cross borders; in unlocking and harnessing new knowledge; in building cultural and political understanding; and in modeling environments that promote dialogue and debate… The ideal and breadth of liberal education that embraces the humanities and arts as well as the social and natural sciences is at the core of Harvard’s philosophy. ’/ Drew Gilpin Faust
* The above story is adapted from materials provided by Harvard University