OF Challenges There has been a constant evolution
of OF collection methods and devices during the last two decades. Many de- vices were ineffective and have been withdrawn from the market. Many other devices still have not been sufficiently evaluated to ensure that the volume of OF collected and the precision of the collection volume are consistent. A limited or unknown collection volume, a limited or unknown harvested volume, or inconsistent collection volume all create testing challenges. For example: 1. More sophisticated drug screening and confirmation methods may be needed to achieve the required testing sensitivity.
2. Te limited OF volume may preclude screening or confirmation for the desired number or menu of drugs.
3. Te limited OF volume might also preclude retesting.
4. Device-to-device variable in collection volume adversely affects quantitative measurements and confounds interpre- tation of results.
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To ensure reliable drug test results,
recovery levels for each drug must be known, consistent, and greater than 80 percent. Poor or limited recovery of drugs from collection devices results in testing challenges such as those just described and some drugs and metabo- lites may escape detection, quantitation or reporting. Loss of drug because of instability in
OF can affect detection, quantitation, interpretation and retest results. As stated, under controlled conditions such as frozen storage, most common drugs are reason- ably stable in OF. However, stability is both device and drug dependent. Depending on the collection device, THC stability may be problematic even when OF specimens are frozen. Using some devices, THC was relatively stable for up to six weeks when the OF was stored frozen. However, THC concentrations decreased precipitously when the OF was stored refrigerated for the same time period. At room temperature, some studies have demonstrated significant loss of THC aſter 2 weeks of storage.
OF Opportunities Despite the limitations discussed above,
the advantages of using OF as a testing specimen far outweigh the challenges. OF drug concentrations mirror those of blood drug concentrations providing interpreta- tive insight into the potential effect(s) of the drug on the donor’s behavior or impairment. OF can be collected virtually anywhere. No special facilities are needed; therefore, OF can be collected in clinical setings or at the worksite or roadside. OF collections are fully observed. Observation reduces the risk of specimen manipula- tion such as substitution and adulteration. In contrast to many urine collections, OF collections are discrete, not subject to shy- bladder issues and collectors do not have to be the same gender as the donor. Unlike blood collections, OF collections do not require trained phlebotomists, handling of sharps such as needles or handling of biohazards. From a collector’s perspective, OF collections easily performed, the entire collection can be observed and specimen handling, storage and shipment area less
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