Biomedical Engineering Reference
In-Depth Information
Table 2
Advantages and disadvantages of LC-MS vs. immunoassay (where assays are available)
for therapeutic drug monitoring
Attribute
LC-MS
Immunoassay
Analytical sensitivity
Highest
Suf fi cient for some tests
Analytical speci fi city
Very high
Questionable, antibody dependent
Operator expertise
High
Low
CLIA test category
Highly complex
Moderately complex
Instrument costs
High
High
Reagent costs
Low
High
Commercial availability
Lab developed test
Unavailable for most drugs of interest
Turnaround time
30-60 min
10-20 min
Random access
Limited
Widely practiced
Multiplex capability
Available
Not possible without multiple assays
3
Analytical Testing Platforms for Therapeutic Drug
Monitoring
Pharmacogenomic testing for routine clinical practice is still in its infancy. Relabeling
mandates and black box warnings issued by the Food and Drug Administration has
accelerated the clinical interest in pharmacogenomic testing for select drugs. Critics
to routine implementation have argued that genetic testing only accounts for some
of the variability in drug response or prediction of adverse events. Therefore, other
predictive phenotypic tools are needed, such as functional testing and therapeutic
drug monitoring. The debate regarding the clinical significance of genotyping vs.
phenotyping will continue for years to come. Each approach has its advantages and
disadvantages. It is likely that optimal patient management will require a combina-
tion of both approaches. However, doing both testing may not be a cost-effective
strategy unless it can be shown that the improvements in clinical outcomes justify
additional costs. If therapeutic monitoring is important for the drugs discussed in
this chapter, LC-MS appears to be the analytical method of choice. LC-MS enables
detection of parent and metabolite concentration in the same analytical assay.
Specific immunoassays for these and other drugs of pharmacogenomics interest are
not commercially available. The analytical sensitivity of LC-MS is superior to
immunoassays. Table
2
summarizes some of the advantages and disadvantages dif-
ferences between these two analytical approaches for a variety of attributes.
References
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