Many technologies have made the transition from R&D labs to clinical labs, so it is not surprising that MS has as well. Starting in the 1970s with GC/MS, up to today and the use of LC-MS/MS, the adoption of MS by clinical labs has grown. For small molecules, LC-MS/MS’s high accuracy has made it an important technique for certain clinical testing applications. In addition, improvements in robustness, ease of use and throughput have increased the utilization of LC-MS/MS for clinical applications. With several MS companies targeting the market, advances in automation, method development and sample preparation continue. However, LC-MS/MS remains far from a routine technique in diagnostic labs and, according to many observers, still requires further enhancements to make it amenable for use by a majority of clinical labs. In particular, developments related to instrument operation, sample preparation and standardization are required to realize LC-MS/MS’s full diagnostic potential.

The rapid adoption of LC-MS/MS by clinical labs began in the 2000s when advancements in MS technology, such as the development of atmospheric pressure ionization, enabled easier sample preparation and higher throughput. “The huge increase in MS testing that occurred in the 2000s was due to the realization that MS offered the ability to test with sensitivity and specificity,” said David Herold, MD, PhD, chief of Clinical Chemistry at the Veterans Administration Medical Center in San Diego; professor of Pathology at the University of California, San Diego; and president and Board chair of the Association for Mass Spectrometry: Applications to the Clinical Laboratory (www.msacl.org).

Compared with existing clinical methods, LC-MS/MS’s higher specificity enables the detection of lower levels of analytes, as well as the enhanced detection of analytes in the presence of interferences, such as matrix effects. It also allows for the simultaneous detection of multiple analytes. These advantages translate into economic advantages, such as faster assay development and testing, as well as the development of assays for which alternatives are unavailable.

The most widely used applications for LC-MS/MS in clinical labs are testing for drugs of abuse, vitamin D, testosterone, and immunosuppressants as well as for newborn screening, according to Dr. Herold. For drugs of abuse, LC-MS/MS enables screening and validation in one run and the simultaneous monitoring of multiple drugs. For testing levels of vitamin D, LC-MS/MS provides better specificity than immunoassays, including quantitation of two forms of vitamin D. LC-MS/MS is also used for steroid testing, most notably testosterone testing, for which LC-MS/MS can quantify the low levels found in women and children. Immunosuppressant testing is one of many therapeutic drug-monitoring (TDM) applications for LC-MS/MS. Advantages include the simultaneous measurement of a patient’s immunosuppressants (cyclosporin, tacrolimus, sirolimus or everolimus) after an organ transplant.

Of these applications, the use of LC-MS/MS for screening of newborns for metabolic disorders is among the most widely adopted. Using LC-MS/MS, labs can screen for more than more than 30 metabolic conditions. US states mandate the screening and a number of FDA-approved assays are available. PerkinElmer leads the market for MS-based newborn-screening systems. The triple quadrupole MS instruments for these systems are supplied by Waters.

In addressing clinical markets for LC-MS/MS, each MS manufacturer has utilized their technologies to differentiate their offerings and provide a competitive solution. “AB SCIEX offers the largest portfolio of MS systems that are directly applicable to the clinical research market, ranging from entry level to the highest performance systems on the market,” said Joe Anacleto, vice president and general manager of Applied Markets and Clinical Research at AB SCIEX. He described the API 3200 system as economical and designed for routine research applications, such as studies of inborn errors of metabolism, TDM and vitamin D. The company’s API 3200 LC-MS/MS system and its hybrid linear ion trap MS systems are also used for clinical applications. “The triple quadrupole and QTRAP 5500 instruments provide the highest performance for method development, quantitation and analysis that require the ultimate in sensitivity, like low-level steroids and 1,25-Dihydroxyvitamin D3 and D2.”

Asked about fast-growing applications, Mr. Anacleto told IBO, “There are a number of ‘hot’ applications in the clinical research market, but the one that tends to stand out in the last couple of years is vitamin D analysis.” For vitamin D analysis, he said MS’s advantages include “greater selectivity and specificity, better sensitivity, simplified sample preparation, short run times, the ability to analyze multiple compound classes in a single run, and ultimately a better return on investment.”

As for AB SCIEX’s plans for the clinical market, Mr. Anacleto commented, “This is one of our fastest-growing markets, and we are continuing to invest in advancing our system solutions to meet growing customer needs.” These investments include the development of more complete solutions that are easier for customers with no MS experience to use.

Future plans also include regulatory approval. “AB SCIEX will continue to invest within the clinical market through product development, marketing, customer education and support, as well as seeking regulatory approval for our systems in specific countries, including the US,” explained Mr. Anacleto. “We are still in the early stages of executing our regulatory strategy, and we intend to provide more information as we move down that path.”

Currently, Waters is the only manufacturer to offer FDA-approved assays for LC-MS/MS clinical diagnostics. In 2004, Waters entered into an agreement with Chromsystems GmbH to supply the chemistries. In 2009, AB SCIEX (at that time, Applied Biosystems) also agreed to distribute the company’s clinical kits for LC-MS/MS.

Like AB SCIEX, Thermo Fisher Scientific plans to pursue regulatory approval for its clinical MS kits. “We are working with our clinical diagnostics business to develop a series of kits for which we will seek FDA clearance,” stated Greg Herrema, senior vice president of Thermo Fisher Scientific and the president of Analytical Technologies. Last year, Thermo released its first research use–only reagent kit for clinical MS, the Thermo Scientific ClinSpec Immunosuppressants Test (see IBO 7/31/10).

Thermo Fisher Scientific’s involvement in the clinical LC-MS/MS market extends to many applications. “Our MS platform in combination with our expertise in clinical diagnostics provides researchers with an advantage in a number of scientific disciplines, including toxicology, endocrinology and drug monitoring,” said Mr. Herrema.

The development of robust workflows has been a focus for the company. An example is the Thermo Scientific Transcend TLX System. “Two of the key challenges in applying MS to clinical research applications are matrix interference and throughput. Our Transcend TLX systems provide a striking advantage in tackling both challenges: multiplexing up to four LC channels seamlessly and automatically, while also applying two-dimensional chromatography enabling on-line cleanup based on Turboflow technology,” noted Mr. Herrema. Turboflow technology allows for the direct injection of biological samples into the mass spectrometer. “This achievement gives the user a streamlined sample prep workflow and increased ruggedness, so that system performance stays stable over a larger number of samples.”

In addition to technology development, other factors are also driving growth. “There is a growing demand for LC/MS methods for use in clinical research across Europe,” noted Mr. Herrema. As for the US, he told IBO, “the most marked growth has been in the area of pain management.” Initially adopted by large reference labs, LC-MS/MS is increasingly being used by other types of labs. “We are now seeing a trend where smaller laboratories and contract labs are adopting the technology to bring testing, that would have otherwise been sent out, in house to save money,” said Mr. Anacleto.

Despite the many advantages of LC-MS/MS, the technique has not been widely adopted by clinical laboratories. Dr. Herold estimated that, outside of drugs-of-abuse validation, less than 5% of clinical labs use MS. Although much progress has been made in recent years, major impediments to adoption continue to be cost, complexity, laborious sample preparation and lack of testing standardization.

Among the improvements that would lead to wider adoption are to make LC-MS/MS systems as easy to operate as clinical analyzers. “The instrument manufacturers need to develop systems that integrate into the workflow of the clinical laboratory,” said Dr. Herold. “This will require simplification of operation so it can be run by available medical technology staff, random access so that tests can be run in a non-batch mode, [and] an extensive menu so the instrument satisfies a significant clinical need.”

Greater adoption will also depend on higher throughput. “Once you get to the point where you have a throughput of analytes that is in excess of 10,000 analytes per instrument on what I call ‘high-value tests,’ you then start getting to the point where you can really afford to have a mass spectrometer,” explained Dr. Herold. “But the reality of it all is once you get a mass spectrometer in, and you’re able to get it to the degree of automation that should be available in the near future, you’ll be able to run between 60,000 and 100,000 tests, which then makes it extremely valuable. “

The lack of standardization of clinical assays has also been an issue, resulting in inter-lab variability. The Endocrine Society introduced a resolution last year calling for the standardization of testosterone assays, with a time line of 2012. “Most of the issues around standardization have to do with inadequate assay performance, the differences in opinion on consensus on use, and the lack of reference ranges,” explained Mr. Anacleto. AB SCIEX is collaborating with the Centers for Disease Control on standardization of testosterone measurement. “The College of American Pathology challenge tests have to be accuracy based, not consensus based. This will require that standards and control will need to be developed and sourced to established reference material,” said Dr. Herold.

The rapid progress made by LC-MS/MS in clinical labs is expected to continue. Instrument makers are optimistic about further adoption, driven by technology advancements, as well as by labs’ greater exposure to the technique. “Going forward, the industry will be focused on better integration with existing LIMS systems, smaller instruments and more automated sample preparation,” said Mr. Anacleto. Mr. Herrema foresees market demand also helping adoption. “As requests for clinical lab tests become more routine, patients and doctors will want accurate results quickly. Conducting clinical research is essential to achieving that goal,” he said.

Dr. Herold said he believes the availability of FDA-approved tests is important for advancing the use of LC-MS/MS by clinical labs. “The adoption of this technology beyond those laboratory settings where there is already a strong MS presence would require the introduction of FDA-approved tests and, likely, instrumentation,” he told IBO. Above all, he stressed the role that LC-MS/MS can play in improving patient care and reducing health care costs by enabling new clinical analyses that lead to better diagnostic understanding.