WASHINGTON – Advances in a powerful lab technology known as mass spectrometry are beginning to revolutionize all areas of medical testing. The Mass Spectrometry issue of Clinical Chemistry, the journal of AACC, showcases the breadth of this technology’s impact on patient care—from making it easier to determine whether diabetes patients are at risk for life-threatening cardiovascular events, to reducing the amount of surgical procedures cancer patients must undergo.
People with diabetes are two to four times more likely to develop cardiovascular disease than unaffected individuals. Monitoring diabetes patients’ risk of heart attack, stroke, or cardiovascular death is therefore critical to ensuring that preventive measures are taken before these potentially fatal events occur. The type of haptoglobin (a protein that binds to hemoglobin in the blood) that a diabetes patient has is an important factor in determining his or her risk of heart attack or stroke. Current methods for identifying haptoglobin type, however, are too time-consuming, and clinical labs are in need of a reliable haptoglobin test that is fast enough to screen large batches of samples.
By modifying a type of mass spectrometry known as matrix-assisted laser desorption/ionization time of flight (MALDI-TOF), a group of researchers led by Petr Novák, PhD, of Charles University in Prague, Czech Republic, has developed a rapid haptoglobin test that will help diabetes patients to learn their risk of cardiovascular disease and receive treatment in a timely manner. One of the most time consuming parts of haptoglobin testing is that labs must extract haptoglobin from blood samples using antibodies that grab onto the protein so that its type can be identified in a separate analysis step. Novák’s team sped up this process by attaching haptoglobin antibodies directly to the sample plates that MALDI instruments analyze, thereby consolidating the extraction and analysis stages.
Using 116 blood samples, they tested their “laboratory on a plate” method—known as direct immunoaffinity desorption/ionization (DIADI)—and also confirmed its results using the proven lab method Western blot. DIADI found 52 individuals with haptoglobin type 2-2, 47 with type 2-1, and 17 with type 1-1. The results obtained by Western blot were in 100% agreement.
“The presented method for phenotyping of haptoglobin by immunoaffinity enrichment combined with MALDI mass spectrometry is rapid, does not rely on external purification steps, can be automated, and consumes amounts of antibody comparable with those for standard ELISA,” said Novák. “It has a potential not just for haptoglobin phenotyping but also for high-throughput mass spectrometry determination of other clinically relevant antigens.”
Another novel mass spectrometry method shows potential as a way to make cancer surgery more precise. When a tumor is surgically removed, a rim of normal tissue around it known as the surgical margin is also taken out. During or after surgery, a pathologist then examines the surgical margin, typically by studying it under a microscope, to ensure that it does not contain any cancer cells. If it does, additional surgery is usually needed.
In a review article, Demian R. Ifa, PhD, of York University, Toronto, and Livia S. Eberlin, PhD, of the University of Texas at Austin, describe numerous emerging techniques based off of ambient ionization mass spectrometry that could enable evaluation of the surgical margin to happen in real time. One remarkable example of these is the intelligent knife, or iKnife, which couples electrosurgical devices to mass spectrometry and multivariate statistical programs. In cancer cases where electrosurgery is needed, this enables a sample of the surgical margin to be taken, chemically and statistically analyzed for cancer cells, and for a surgeon to receive the result on an operating room screen all in a mere 0.7–2.5 seconds. This immediate evaluation could greatly enhance surgeons’ ability to remove all of a tumor on the first try, eliminating the need for follow-up surgeries.
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Dedicated to achieving better health through laboratory medicine, AACC brings together more than 50,000 clinical laboratory professionals, physicians, research scientists, and business leaders from around the world focused on clinical chemistry, molecular diagnostics, mass spectrometry, translational medicine, lab management, and other areas of progressing laboratory science. Since 1948, AACC has worked to advance the common interests of the field, providing programs that advance scientific collaboration, knowledge, expertise, and innovation. For more information, visit www.aacc.org.
Clinical Chemistry is the leading international journal of clinical laboratory science, providing 2,000 pages per year of peer-reviewed papers that advance the science of the field. With an impact factor of 7.9, Clinical Chemistry covers everything from molecular diagnostics to laboratory management.