“Looking back at the past 5 years, what do you think are the most important developments in infectious-disease testing?” We posed this question to six experts with varied backgrounds, and we heard three common replies: nucleic acid testing, automation, and a focus on safety in health care.
Better Diagnostics: Nucleic Acid Testing
Steven H. Hinrichs, MD, Stokes-Shackleford professor of pathology in the department of pathology/microbiology; director of the Center for Biosecurity; and director of the Nebraska Public Health Laboratory, all at the University of Nebraska Medical Center (UNMC of Omaha), says that molecular methods for the identification of infectious diseases has been one of the most important developments in infectious disease testing during the past few years.
“The role of nucleic acids and DNA/RNA testing methods have been one of the most important developments in the field,” agrees Pat Balthrop, president and CEO of Luminex Corp (Austin, Tex).
The eBDS system detects bacterial contamination of platelets.
Nucleic acid tests, cited by half of our experts, identify infectious organisms through the detection of specific DNA or RNA sequences. Probe-based methods “use a small fragment-labeled DNA that hybridizes (binds) to a target sequence from the organism,” while “amplification tests use a technology that causes a target sequence from the organism to be duplicated many thousands of times.”1
Amplified assays can generate a 10 billion-fold increase in the target, making these methods extremely sensitive. However, they are not error-free—false positives and false negatives are still possible, and confirmatory tests are often required. Because of the faster turnaround and higher sensitivity, however, confirmation is typically sought by testing for another nuclear target, when one is available, rather than with culture.
The Leuokotrap Affinity Prion Reduction Filter is designed to do just that: filter prions from the blood supply.
Though the tests using nucleic acid testing and nucleic acid amplification technology were first approved by the US Food and Drug Administration (FDA) in 1987 and 1993, respectively, improvements in methods and technology have increased their value to the clinical lab over the past few years. The advances in this area have been driven in part by the effort to sequence the human gene through the Human Genome Project. One of the effort’s early goals was to see a two- to threefold improvement in sequencing throughput while reducing cost.2 By 2002, the program had surpassed its goal of sequencing 500 Mb per year at less than 25 cents per finished base with a standard of more than 1,400 Mb per year at less than 9 cents per finished base.2
Annette Adelman is a product manager, infectious disease, with DiaSorin, a private company, based in Stillwater, Minn, that develops and manufactures reagents for in vitro diagnostics. Adelman believes automation is one of the most important developments to have occurred in infectious disease testing.
Pat Balthrop is president and CEO of Luminex Corp. The company, located in Austin, Tex, develops, manufactures, and markets proprietary biological testing technologies with applications throughout the life sciences industry. Balthrop cited nucleic acid testing and automation, in addition to a constant focus on accuracy, as important developments in the field.
Eric Bouvier is president and CEO, North America, for bioMérieux Inc. Headquartered in France with offices in Durham, NC, the worldwide group specializes in the field of in vitro diagnostics for clinical and industrial applications. Bouvier noted the increasing role of automation as a recent advance with great impact.
Joseph S Cervia, MD, FACP, FAAP, is professor of clinical medicine and pediatrics at Albert Einstein College of Medicine in the Bronx, NY, and medical director and senior VP of Pall Corp. Pall, located in East Hills, NY, specializes in filtration and complementary technologies. Cervia believes the focus on medical safety, particularly with regard to the health care environment, has led to significant advances in patient care.
Steven H. Hinrichs, MD, is the Stokes-Shackleford professor of pathology in the department of pathology/microbiology; director of the Center for Biosecurity; and director of the Nebraska Public Health Laboratory, all part of the University of Nebraska Medical Center (UNMC of Omaha). Hinrichs cited molecular diagnostics and automation as two of the field’s most important developments.
Thomas Scott Jones is the director of laboratory services for the South Texas Blood and Tissue Center in San Antonio. The center is a non-profit community resource that collects and tests more than 200,000 components of blood and tissue annually. Jones states that automation has been a tremendous development, particularly from the standpoint of those specializing in blood banking.
Faster, cheaper sequencing, combined with improvements in nucleic acid-extraction techniques, developments in nucleic acid amplification, and commercial availability of molecular-detection methods, have contributed to the rise in nucleic acid diagnostics.
“With nucleic acid testing, we are not looking for antibodies but for the actual viruses and contaminants themselves, significantly decreasing the time needed for detection,” says Thomas Scott Jones, director of laboratory services at the South Texas Blood and Tissue Center in San Antonio, Tex.
The advance has been critical for blood banking, enabling a big increase in the safety of blood components, Jones adds. It has also been critical to clinical labs, which have seen turnaround times improve dramatically with nucleic acid tests and nucleic acid amplification testing, in some cases from weeks to hours.
Multiplexing, which allows simultaneous detection of multiple markers in one sample, has added new efficiencies. Balthrop cites avian flu as an example. “Everyone’s watching for avian flu, but upper respiratory symptoms are vague. It’s a bit useless to perform an individual test for avian flu when it’s very likely that avian flu is not the diagnosis. We prefer to check for many things at once to identify what the condition actually is,” Balthrop says, noting that new markers can be added to an already-existing panel.
With automation, nucleic acid testing has become even more efficient. “Technology has enabled us to perform assays using an automated process that can reduce turnaround time to 45 minutes from 3 or 4 hours,” says Annette Adelman, product manager for infectious disease, DiaSorin (Stillwater, Minn).
“Automation has been huge,” Jones says. His lab is in the process of installing an antibody system and next year will bring in one to perform nucleic acid testing.
Automation of any process impacts performance in a variety of ways. Research and case studies have shown that the use of these systems results in shorter turnaround times; reductions in laboratory errors; and efficiency gains in time, personnel, and cost. For example, Sarkozi et al report a nine-fold improvement in productivity in the chemistry lab with the introduction of automated systems.3 They also noted a reduction in errors.3
Adelman adds that automation streamlines laboratory processes, eliminates the need for subjectivity in result analysis, and creates time for technologists who are typically overworked due to staffing shortages.
Legionella can contaminate a hospital’s water supply.
As automation becomes more prevalent in the lab, the demands change. The need for systems with multifunctionality or those designed for preanalytics has grown, and manufacturers are responding. “Years ago, the typical lab would house several large machines that performed one function each. Now, it is necessary for one instrument to perform all of the tasks that a lab full of equipment used to do, and it must take up less space,” says Eric Bouvier, president and CEO, North America, bioMérieux Inc (Durham, NC).
Jones agrees that new systems are doing more. Looking 5 to 10 years into the future, he envisions fully automated labs with conveyor belts and tubes. “When you are processing thousands of samples a day, there is no way around human fatigue,” he says.
By eliminating manual steps, the process becomes less prone to operator error. “Automation provides consistent results versus manual methods,” Adelman says, citing as an example the use of bar coding to avoid misidentification.
Data collected on errors indicates that a greater number occur in the pre- and post-analytic stages. In 2002, an Italian group conducted a review of the literature published during the previous 8 years and found that 68% to 87% of errors were reported in these two stages.4
Automation will help improve that figure. Front-end systems will complete tasks in the preanalytic phase, while decision-making software will reduce errors in the postanalytic phase. Bouvier notes that clinical decision-support tools, used in conjunction with appropriate diagnostic-testing procedures, ensure delivery of the “right information to the right person at the right time.”
Safer: Focus on Improving Care
Greater patient safety is not only the result of automation, it is also a driver. In 1999, the Institute of Medicine (IOM of Washington, DC) determined that between 44,000 and 98,000 American patients die annually due to medical error. The report did not specify where in the process those errors occurred, but it did create a stir in the medical community. The community has been looking inward ever since.
“Current efforts and mandates around both patient safety and quality improvements continue to grow. One consequence of both the increased concern regarding patient safety, as well as the rise in medical costs, is the new Pay for Performance (P4P) initiative. Those hospitals that perform better will earn more reimbursement. Those that do not, will not,” Bouvier says.
Despite the hardships this may bring for individual institutions, Bouvier feels that initiatives, such as P4P, may help to increase the value of the clinical lab, because results, information, accuracy, and turnaround time all become more critical factors.
Labs already play a role in monitoring the health of a hospital, since, through nucleic acid diagnostics, they detect nosocomial infections. “Many outpatient-acquired infections are easily diagnosed and readily treatable. Ironically, it’s those acquired in the health care setting that can be more severe—more difficult to diagnose and treat,” says Joseph S Cervia, MD, FACP, FAAP, professor of clinical medicine and pediatrics at Albert Einstein College of Medicine (Bronx, NY) and medical director and senior VP of the Pall Corporation (East Hills, NY).
“We are only now getting a better understanding of the factors that contribute to risk in the hospital setting,” Cervia says. He suggests that more research needs to be done to better understand what places patients at risk and what can be done to counter those risks.
Cervia notes that water is one factor that has recently come under the radar. “Water is a necessary element to health care, but it usually harbors pathogenic microbes that pose a threat to patients and staff that come into contact,” Cervia says. Microscopic filters and systemic systems are being refined to reflect this reality.
A microscope has also been taken to blood, particularly the blood supply, another vulnerability. “In the hospital setting, one of most frequent problems is bacterial contamination of platelets used for transfusions. A bacterially contaminated platelet unit can kill a patient in hours. So now, platelets are tested prior to dispensing,” Cervia says. New tests have been developed to improve sensitivity.
No tests have yet been developed to detect prions, infectious proteins that are believed by some to be the cause of conditions such as Creutzfeld-Jakob disease (CJD), otherwise known as mad cow disease. Since prions contain no genetic sequences, but are rather an end product of genes, nucleic acid tests are ineffective. With no way to detect or identify them, the blood supply is at risk. Cervia notes that products are in development that will filter the blood of prions, a step that can be incorporated into the already-existing screening process.
And so development marches on. “Nearly all medical laboratories are facing a number of challenges that impede an effective and productive workflow, including increasing workloads, a decline in skilled laboratory personnel, and the loss of established and knowledgeable personnel to retirement,” Bouvier says. Nucleic acid tests, automation, and the focus on safety have helped address some of these issues. What additional help they will offer or what new advances will follow remain to be seen.
Nucleic acid tests identify viruses by detecting their DNA or RNA sequences. In 1987, Gen-Probe Inc’s test for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) infections became the first nonradioactive direct-specimen genetic probe diagnostic to receive clearance by the US Food and Drug Administration. Now, there are a host of tests. As of August 15, 2005, the following tests have been cleared for similar use:1
For single-organism detection of Chlamydia trachomatis:
For single-organism detection of Neisseria gonorrhoeae:
For detection of Chlamydia trachomatis and Neisseria gonorrhoeae:
There are also automated systems to run nucleic acid diagnostics. These include:1
Renée DiIulio is a contributing writer for Clinical Lab Products.
1. Gen-Probe. Nucleic acid tests. lab-education.org. Available at: www.lab-education.org/review_ed_mod/mod01_slide61.htm. Accessed January 14, 2006.
2. Sequencing technologies. The Human Genome Project. September 2004. Available at: http://www.ornl.gov/sci/techresources/Human_Genome/research/ instrumentation.shtml. Accessed January 14, 2006.
3. Sarkozi L, Simson E, Ramanathan L. The effects of total laboratory automation on the management of clinical chemistry laboratory. Retrospective analysis of 36 years. Clin Chim Acta. 2003;329:89–94.
4. Bonini P, Plebani M, Ceriotti F, Rubboli F. Errors in laboratory medicine. Clin Chem. 2002;48(5):691–698.