Test Details
Methodology
Liquid chromatography/mass spectrometry (LC/MS)
Result Turnaround Time
2 - 5 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Monitor therapeutic levels of propoxyphene (Darvon®).
Limitations
This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.
Custom Additional Information
Propoxyphene is an analgesic that is structurally similar to methadone. Its metabolite, norpropoxyphene, is also pharmacologically active. Toxic effects include nausea, vomiting, and progressive central nervous system depression. Toxicity is additive with ethanol. Toxicity can be neutralized by narcotic antagonists. Peak serum level occurs two hours postoral dose; half-life is 8 to 24 hours. Propoxyphene can also be measured in urine as part of a drugs-of-abuse evaluation.
Specimen Requirements
Specimen
Serum or plasma
Volume
1 mL
Minimum Volume
0.3 mL
Container
Red-top tube, lavender-top (EDTA) tube or green-top (heparin) tube. Do not use a gel-barrier tube. The use of gel-barrier tubes is not recommended due to slow absorption of the drug by the gel. Depending on the specimen volume and storage time, the decrease in drug level due to absorption may be clinically significant.
Collection Instructions
Collect specimen immediately prior to next dose.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
Therapeutic: 100−400 ng/mL
Storage Instructions
Room temperature
Causes for Rejection
Gel-barrier tube
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 084756 | Propoxyphene, Serum | 3543-6 | 084757 | Propoxyphene,Serum | ng/mL | 3543-6 |
| Order Code | 084756 | |||||
| Order Code Name | Propoxyphene, Serum | |||||
| Order Loinc | 3543-6 | |||||
| Result Code | 084757 | |||||
| Result Code Name | Propoxyphene,Serum | |||||
| UofM | ng/mL | |||||
| Result LOINC | 3543-6 |