Confirmation Testing Q&A (part 2)

Dr. Joseph E. Graas, Scientific Director
Dr. Edward Moore, Medical Director

Is one confirmation methodology better than another?

The type of confirmation utilized by a program isn’t necessarily “better” than another method; it depends upon the program’s and patient’s needs.  While GC/MS is widely considered “The Gold Standard” of drug-testing, it is typically a more expensive test.  For most substance abuse treatment programs or for non-legal matters, the TLC methodology is sufficient.

There are limitations to what a TLC confirmation can provide, however.  First, a TLC confirmation does not supply quantitative results for each analyte present; only qualitative results are reported.  If a patient’s sample screens Positive for Opiates, a TLC confirmation will provide Positive/Negative results for Morphine, Codeine, Hydrocodone, Hydromorphone and 6-MAM, but no values are assigned.  A GC/MS or LC/MS/MS confirmation will provide values for any drugs detected.

Second, due to limitations in the technology, a TLC confirmation cannot be performed for certain drugs (see table to right for analytes confirmed by SDRL).  It is possible, however, to use multiple confirmation methodologies on the same sample (i.e.  TLC for Amphetamines and GC/MS for Benzodiazepines).