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HelpTest Code Billings Clinic: 8603 Mayo: MEPHS Mephobarbital and Phenobarbital, Serum
Reporting Name
Mephobarbital and Phenobarbital, SPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Monitoring of mephobarbital and phenobarbital therapy
Method Name
Gas Chromatography Mass Spectrometry (GC-MS)
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Red top (Serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 2.0 mL
Collection Instructions:
1. Collect specimen immediately before next scheduled dose.
2. Centrifuge and aliquot serum into plastic vial within 2 hours of collection.
Specimen Type
Serum RedSpecimen Minimum Volume
0.7 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Refrigerated (preferred) | 14 days | |
| Ambient | 14 days | ||
| Frozen | 14 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
MEPHOBARBITAL
Therapeutic range: 1.0-7.0 mcg/mL
Toxic concentration: ≥15.0 mcg/mL
PHENOBARBITAL
Therapeutic range
Children: 15.0-30.0 mcg/mL
Adults: 20.0-40.0 mcg/mL
Toxic concentration: ≥60.0 mcg/mL
Interpretation
Mephobarbital concentrations above 15 mcg/mL have been associated with toxicity.
Phenobarbital concentrations between 35 and 80 mcg/mL have been associated with slowness, ataxia, and nystagmus, while concentrations above 100 mcg/mL have been associated with coma without reflexes.
Day(s) Performed
Thursday
Report Available
3 to 9 daysTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80184
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| MEPHS | Mephobarbital and Phenobarbital, S | 97183-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 89706 | Mephobarbital, S | 3750-7 |
| 84582 | Phenobarbital, S | 3948-7 |
Forms
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| MBARS | Mephobarbital, S | No | Yes |
| PHBRS | Phenobarbital, S | No | Yes |