Standardization in Molecular Diagnostics: More Critical Now Than Ever
We spoke with Ted Schutzbank, PhD D(ABMM), Scientific Affairs Manager of Diagnostics at Meridian Bioscience about the importance of standardization in molecular diagnostics and the new testing methods available for COVID-19.
What is your role at Meridian Bioscience?
My current position at Meridian Bioscience is Scientific Affairs Manager. My main role is to serve as an educational resource to our sales and marketing groups and to our clients, regarding the clinical utility of our infectious disease–related testing products, especially the molecular product line. I also travel with our sales representatives to give lectures and grand round presentations regarding the clinical utility of specific molecular testing products.
Can you briefly explain the importance of standardization in molecular diagnostic testing?
In my opinion standardization is critical in the area of molecular diagnostic testing. There are many laboratories in the United States and abroad that are running different tests to achieve the same diagnostic goal. An example would be quantitative reverse transcriptase PCR viral load testing for HIV Type 1. There are several commercial tests available for this purpose, but it’s important that the same result be obtained independent of which test is used. Standardization is even more critical where such tests being used are laboratory developed. This is a much more difficult situation since different laboratories will be testing for different molecular targets within the genome of a specific organism, and may use different controls and quantification standards, which may cause differences in test results from laboratory to laboratory.
How is standardization particularly important during the COVID-19 pandemic, in light of the many new tests that have been/are being developed by different industry leaders for use on different platforms?
It’s critical that all laboratories are using tests that detect the same organism, in this case SARS-CoV-2, with the same degree of sensitivity and specificity. At present there are many different tests in use across the United States and the world. Some of these are commercially produced, while others are developed by the testing laboratories. The target genes and DNA sequences may vary widely among all these tests. It’s become apparent that some of these tests vary widely in their clinical performance. Presently, most testing in US hospitals is performed on patients with severe symptoms of COVID-19 who will be hospitalized, as well as healthcare workers, in order to determine their infection status. However, as we move into expanded testing to determine who in the population is infected, and to trace and test their contacts, it becomes even more crucial that no infected individual be missed. That can only be achieved through standardization to ensure equal sensitivity among all tests used for this purpose.
Is point-of-care molecular testing currently available for testing suspected COVID-19 patients? Can you explain how these tests work and how accurate they are compared to in-house laboratory testing?
To date the US Food and Drug Administration has given emergency use access to three commercially available tests. All three tests employ the use of a single-use cartridge that performs the actual testing. One of these products is designed to test nasopharyngeal, nasal, or mid-turbinate swabs placed into a viral transport medium. Nasal washes or aspirates are also acceptable. The results are reported via the instrument’s computer after ~45 minutes. Depending on throughput requirements, one test at a time or up to 80 tests can be run.
A second test also employs a single use cartridge for testing. The test utilizes PCR coupled with lateral flow technology to display the test results. Results are available in 30 minutes.
The third method is designed to be used with nasopharyngeal, nasal, or throat swabs Time to result is 5 to 15 minutes. Swabs collected in viral transport media can be tested in the first two assays. Only swabs transported “dry” to the laboratory can be analyzed with the third test.
Which CLSI molecular standards do you think are particularly helpful to laboratorians during this crisis, and why?
There are several CLSI molecular standards that I think will be useful to labs as they look to adding SARS-CoV-2 RNA molecular testing to their test menu. These include:
- MM03 - Molecular Diagnostic Methods for Infectious Diseases, 3rd Edition
This document discusses several different areas, the understanding of which are key to successfully establishing molecular testing for the diagnosis of infectious diseases. While this document was published in 2015, many of the topics discussed still apply to today’s laboratory.
- MM06 - Quantitative Molecular Methods for Infectious Diseases, 2nd Edition
While to date the vast majority of nucleic-acid amplification tests developed for the detection of SARS-CoV-2 RNA in patient samples have been qualitative, there has been some discussion on the possible need for quantitative testing.
Although sequencing of the SARS-CoV-2 virus has not found clinical utility, it’s highly likely that future epidemiological studies will involve sequencing multiple viral genomes. This document provides guidance that will be very useful for the development and implementation of sequencing methods for such studies. The drawback to this document is that it was published prior to the availability of next generation sequencing methods that are expected to play a major role in such studies.
- MM13 - Collection, Transport, Preparation, and Storage of Specimens for Molecular Methods, 1st Edition
Every clinical test starts with a specimen. The old principle of “garbage in garbage out” applies very much to any clinical test, since the condition of the sample being tested defines the outcome of the results. This document provides excellent guidance to help labs ensure that specimens being tested are properly collected and transported to the laboratory to ensure the stability of the analyte to be tested, in this case SARS-CoV-2 RNA. Since RNA is a labile molecule, it’s essential that the virus particle containing the virus remain intact to minimize degradation of the virus RNA genome. The 2nd edition of this document is currently in the final review and voting stages.
- MM17 - Validation and Verification of Multiplex Nucleic Acid Assays, 2nd Edition
There are many laboratories in the US and worldwide that have designed and developed their own, “in-house” SARS-CoV-2 RNA molecular tests. These tests require rigorous validation studies to ensure that they are appropriate for patient testing. In addition, laboratories that utilize commercially available tests that have received FDA emergency use authorization, or EUA, are still required under CAP/CLIA regulations to perform verification studies to ensure that the test is operating correctly in their laboratory. Many of the SARS-CoV-2 molecular tests, both LDT and commercial, include more than one virus gene target sequence, making them multiplex tests. This document provides guidelines for both the validation of laboratory developed multiplex tests as well as the verification required for commercially developed tests that have undergone regulatory approval.
- MM19 - Establishing Molecular Testing in Clinical Laboratory Environments, 1st Edition
This document will provide excellent guidance for those laboratories that have not performed molecular testing in the past but are considering establishing SARS-CoV-2 molecular testing.
Have you seen any changes in the molecular diagnostics field as a result of the COVID-19 pandemic, or do you foresee any changes?
My crystal ball is a bit cloudy regarding this question. I don’t see major changes overall in the field of molecular diagnostics. Where major changes are needed is in the ability to ramp up the ability to provide large-scale testing in support of future pandemics. This will take coordination between laboratory providers, the federal government, and state public health departments to work out how this can happen. The current pandemic didn’t catch the US completely unawares, as public health officials were sounding the alarms well before it hit our shores. However, we failed to appreciate the magnitude of the pandemic and prepare for it. There were laboratories that were proactive in developing tests, with a big shout out to the University of Washington, but existing federal policies made it difficult for such labs to implement new tests without overcoming complex hurdles. While it’s critically important that the testing be highly sensitive and accurate, it is also critically important to have it available early on during a pandemic to ensure adequate patient testing as well as for testing contacts of infected individuals. Stockpiles of supplies for obtaining patient samples is also critical. Having the testing available without being able to collect samples is relatively useless. Laboratories shouldn’t be wasting valuable time trying to figure out how to make their own swabs and transport medium. In this our country has failed and an important, albeit painful lesson is currently being learned.
Dr. Schutzbank has served on the following CLSI Committees and Subcommittees:
- Expert Panel on Molecular Diagnostics (Current Chairholder)
- Current Document Development Committees on:
- Collection, Transport, Preparation, and Storage of Specimens for Molecular Methods (MM13-Ed2)
- Molecular Testing in Clinical Laboratory Environments (MM19-Ed2 – Current Vice-Chairholder)
- Molecular Methods for Genotyping and Strain Typing of Infectious Organisms (MM24-Ed1 – Current Chairholder)
- Criteria for Laboratory Testing and Diagnosis of Human Immunodeficiency Virus Infection (M53-Ed2 – Current Secretary)
- Past Document Development Committees on:
- Collection, Transport, Preparation, and Storage of Specimens for Molecular Methods (MM13-A)
- Design of Molecular Proficiency Testing/External Quality Assessment (MM14-A2)
- Validation and Verification of Multiplex Nucleic Acid Assays (MM17-A and MM17-Ed2)
- Establishing Molecular Testing in Clinical Laboratory Environments (MM19-A)
- Molecular Diagnostic Methods for Solid Tumors (Nonhematological Neoplasms) (MM23-Ed1)
Dr. Schutzbank received his BA in Biology from Temple University, an MS in bacteriology from Iowa State University, and an MPhil and PhD in Microbiology under the mentorship of Dr. Harry Ginsberg at Columbia University. He worked as a postdoctoral fellow in Dr. Arnold J. Levine’s lab at the State University of New York, Stony Brook. His research interests lie in the area of molecular diagnostics in the area of infectious disease testing and more recently, human genomics and precision medicine. He’s worked extensively in the development of real-time nucleic acid amplification assays for the qualitative and quantitative detection of a wide variety of infectious organisms, to include bacterial and viral agents of human disease. Dr. Schutzbank has over 30 years of experience, mainly in hospital-based and private reference clinical laboratories, as well as several years of experience in the in vitro diagnostics research and development arena. He’s a Diplomate of the American Board of Clinical Microbiology. During his career he’s consulted for several IVD and biotechnology companies, as well as the United States Air Force and the Venezuelan Ministry of Health.