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The impact of the new technology.

There has been a biotechnology explosion in the last 10 years. Reports of discoveries and inventions have become commonplace, as have new applications for old techniques. Refinement of many of these technologies into clinically useful diagnostic and therapeutic modalities has undoubtedly contributed to spiraling health care costs. On the other hand, the new technologies have also provided information and treatment that were previously undreamed of.

The clinical laboratory has experienced its own such revolution during the last decade. Techniques

previously seen only in highly sophisticated research labs can now be easily performed in the routine clinical laboratory, thanks to advances in instrumentation.

During the 1990s, this trend will continue, and it will have a major impact

on the clinical laboratory. Emerging technologies, such as DNA probes and nuclear magnetic resonance, will gain wider use as they are simplified; they will allow the lab to perform new tests and use radically new methods for current tests. Other, more established technologies, such as immunoassays, will continue to evolve; their major impact will be to change the way labs operate. Let's look more closely at these new technologies and their future impact on the clinical laboratory. * Immunoassays. The immunoassay diagnostics

market is expected to top $1 billion by 1993, expanding more than six-fold from the $160 million recorded in 1987, according to Theta Corp., a market research firm.

Many available applications are not yet practical because end users would find them difficult to put in place. There are also many tests for which the basic science research has been completed but reagents are not commercially available. The rate

of development in the biotechnology industry virtually guarantees that the reagents will become available in the near future. The last major impediment to growth, therefore, will be the question of how to move the technology into the clinical laboratory in an easily usable form.

Manufacturers currently take two basic approaches to the issue. One way to simplify testing is to package new methods in a form that can be used by today's chem- istry analyzers. Such applications, for higher-volume tests, permit the laboratory to consolidate workstations and save personnel time and the expense of new instruments-important considerations given the technologist shortage and the reduction of the Medicare capital pass-through. These homogeneous and heterogeneous immunoassay methods depend on a number of currently available technologies and promising new technologies such as chemiluminescence and liposomes.

Many large reference laboratories today perform thyroxine assays on routine profiling instruments. Applications for other tests can be handled on smaller analyzers. These approaches depend on the ability of the instrument to carry out various liquid handling manipulations and require reagents that can be formulated in multiple ways. Expect developments of this kind to continue at a rapid pace.

As chemistry instruments become more sophisticated, the end user will be able to take advantage of their advanced features by performing increasingly complex tests. Chemistry analyzers will be

more appropriately called multidisciplinary test processors or MTPs because of their ability to perform an assortment of different tests linked only by some common steps and common end points. When this occurs, optimistic growth forecasts for immunoassay products may turn out to have been understated.

The other direction that the marketplace and manufacturers are taking is toward the use of random access analyzers able to perform a very broad menu of individual tests. Variety rather than throughput will be the goal.

These instruments will rely on specialized test packs containing all the materials, reagents, substrates, columns, etc. necessary for complex tests. They will be able to perform multiple, dissimilar tests simultaneously since the intelligence will be in the test packs. This development will resemble the one that occurred in the late 1970s when the first dry chemistry system revolutionized clinical laboratory testing.

A few vendors are already bringing out first-generation instruments that can perform therapeutic drug monitoring, pregnancy tests, hormone tests, and infectious disease tests simultaneously. These instruments are great improvements over the current state of the art and serve as harbingers of what is to come.

By the late 1990s, immunoassays will probably be performed no differently from any other routine test. They will not be restricted to a particular laboratory area, unlike their status now as specialized testing. Random access analyses will make immunoassays more readily available and pro-

mote their more common use. As in the past, the availability of a test to clinicians will be a far greater driving force for acceptance than the ability of the test to help in a diagnosis.

What are some of the techniques that will be used? Besides the traditional methods, one can expect to see more sophisticated nephelometric tests, forward light scatter, common-capture assays, and time-resolved fluorescence. All of these techniques are available now in one form or another. The trick will be to automate them in a fashion that makes method advantages transparent to the potential user.

If the early instruments that are just appearing give any indication of what is in store, the laboratory in the year 2000 will have little need for special sections or batch testing except in the most sophisticated areas. Today's sophisticated tests will undoubtedly join the list of relatively common laboratory procedures in the average hospital.

This means that the traditional radioimmunossay laboratory will be supplanted. As new tests are converted to other immunoassay methods, the laboratory will have less and less need for the traditional RIA mode of testing.

The number of instruments on the market will skyrocket, driven by advances in robotics, computers, and reagents. Look for the small companies in the high technology parks to do for immunoassays what Silicon Valley did for the home computer market. The growing list of small high tech firms spells a bright future for immunoassay. With the diversity of manufacturers and the differences

in their solutions to the problems, the market will grow strongly.

In fact, laboratory directors in the future may have to grapple with the problems of decentralized immunoassay tests just as they are beginning to solve the problems of distributed testing for so-called routine analytes. * Biosensors. A biosensor is a microelectronic device that uses a biological molecule, such as an antibody or enzyme, as a sensing element. The device usually consists of two major components: a biological recognition unit and an internal sensor.

It is particularly well suited to decentralized testing sites, such as emergency rooms, operating rooms, and physician offices. As a portable hand-held device, a biosensor could simultaneously measure multiple analytes from a single whole blood microspecimen. If implanted in a patient, it could provide real-time biochemical monitoring.

The potential advantages of biosensors include simple and low-cost instrumentation, fast response times, minimum or no specimen pretreatment, and high specimen throughput. These benefits are particularly important in decentralized testing sites, where operators may have limited skill in performing tests.

Unfortunately, many biosensors require frequent calibration and have a limited working lifetime. The technology must also be mass-produced, perhaps on a chip, in order to make it an economically viable alternative or replacement to conventional testing methods. As these problems are overcome during the next decade, biosensors will find their place at

a variety of clinical sites, such as the decentralized lab.

Imagine a complete 12-test profile performed on a drop of whole blood at the bedside of an emergency room patient, all in less than a minute. Though the reagent costs of such a technology may be considerably more than conventional reagents, the added convenience and rapid turnaround time may be justified in some clinical settings.

How much of an impact will biosensors have in the 1990s? Some market analysts, such as

Frost & Sullivan, have predicted a $400 million biosensor market within the next two years, though most of the market will probably not be directly in the clinical laboratory field, but rather in the food industry, environmental services, and other areas. * DNA recombinant technology. Recombinant DNA technology has rapidly extended from the research environment to the clinical laboratory in the form of molecular hybridization assays for detecting specific nucleic acid sequences. These are commonly re-

ferred to as DNA probes. Here's how they work:

A highly specific probe can be made by tagging a single strand of nucleic acid (either DNA or RNA) that is unique to a target antigen, such as is present on a microbe. The probe can then reassemble or "hybridize" with the complementary single strand of nucleic acid that is in the specimen undergoing analysis. Thus new DNA molecules are constructed in vitro.

Probes can be labeled with a variety of tags, such as radioisotopes, biotin-avidin, enzymes, and chemiluminescent materials, making them potentially applicable to a variety of detection systems. Obviously, the major advantage of DNA probes is that they detect the genetic material itself rather than proteins or antigens that are expressed by the genes. Theoretically, this should make the assay highly specific. Unfortunately, in many instances the sensitivity of the method must be improved, since it is often no better than that, of existing methods.

Nucleic acid probes are being used in several diagnostic kits. For instance, they can now pro vide rapid detection of certain mycobacteria, a process that previously required weeks of traditional culture for these slow growing organisms. During the next decade, expect DNA probe assays to become more commonplace in the microbiology lab, replacing or supplementing traditional culture techniques. They will be particularly useful on organisms such as Legionella and the tubercle bacillus, for which present culture techniques are difficult or lengthy.

Probes can also detect nonvia-

ble organisms, a specific organism in a mixed culture, and latent viral infections which do not produce detectable antigens or proteins), such as HIV, herpes, and cytomegalovirus.

By some estimates, 1 to 2 per cent of all specific pathogen tests will use DNA probes during the next three or four years, with the total worldwide market exceeding $600 million.

Other applications for DNA probes include paternity and forensic testing ("genetic finger- printing"), identification of genetic disorders, and tumor probes. Currently, probe-based tests are available for prenatal diagnosis of sickle cell anemia, cystic fibrosis, and hemophilia. The cost of doing many of these tests is often pro- hibitive, though over a period of time costs will almost certainly drop as more laboratories provide the service and economies of scale are realized.

Cancer probes will be able to detect oncogenes (genes involved in producing tumors), abnormalities, and viral DNA associated with tumors, such as human papilloma virus. The ability of a probe to localize the origin and site of the tumor will be extremely useful in clinical patient management.

Although manufacturers will develop new tests and techniques, most special applications will be too infrequently performed for use by routine clinical laboratories. Instead these tests will be offered by reference laboratories, where economies of scale can be realized.

Perhaps the most significant underlying market force in this area will be the development of automated instrumentation to per-

form the assays. This will simplify the technique so that it can be done by technologists whose DNA probe expertise is limited. When that occurs, the technology will be more widely used in the clinical laboratory. * Nuclear magnetic resonance. Nuclear magnetic resonance (NMR) has been one of the most powerful-and expensive-diagnostic tools in clinical medicine. In recent years, NMR imaging has been used with increasing frequency, often as a more sensitive technique than computerized tomography. In the clinical laboratory, high-resolution NMR spectroscopy can be used to study different compounds.

How does NMR work? It measures the spin of protons in a magnetic field after a radiofrequency current has been applied. In the absence of a magnetic field, all nuclei in a specimen are randomly oriented. However, when the specimen is placed in a magnetic field, the nuclei orient themselves paralle) or anti-parallel to the magnetic field. These two different orientations correspond to slightly different energy states. By applying a radiofrequency energy source, nuclei in a lower energy source can be promoted to a higher one, and the amount of energy that is absorbed or released can be measured. Since all nuclei of a given structure resonate at exactly the same frequency, a compound can be identified by its characteristic absorption peaks. Though NMR spectroscopy is less sensitive than other available techniques, such as high pressure liquid chromatography, it is a nondestructive method that conserves specimens for use in other

laboratory tests. Potential applications of this technology include the identification of drugs and their metabolites and hormones in blood, urine, and other body fluids. One advantage for toxicology is that no special reagents are necessary for specific analytes, so that NMR could be used as a screening method, albeit a relatively insensitive and expensive one, given current technology.

Chances are that nuclear magnetic resonance will not become a mainstay of the routine clinical laboratory during the next decade. On the other hand, exciting new applications of this technology in laboratory medicine will probably mean that it will find a niche in reference laboratories.

Gas chromatography-mass spectroscopy is also an example of how extremely sophisticated technology can migrate to the clinical laboratory. Once merely a research tool, it was increasingly needed as a highly sensitive and exquisitely specific method for use in drug screening confirmation. In less than five years, the technology has changed from a relatively cumbersome tool to a much more simple instrument that has retained every bit of its analytical power.

We can expect GC-MS to gain further acceptance in the laboratory as what were formerly research applications become easier to do. The key to this change is microprocessor-controlled instruments that assist the operator in operating the analyzer and help avoid errors.

Thanks to all of these new technologies, laboratory medicine promises to improve and make even greater contributions to patient care.
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Title Annotation:technological innovations in laboratory medicine
Author:De Cresce, Robert P; Lifshitz, Mark S.
Publication:Medical Laboratory Observer
Date:Jul 1, 1989
Previous Article:Quality management: watchword for the '90s.
Next Article:Trends in regulation and reimbursement.

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