Phenobarbital Level

Abbrev Code:PHENO   
Order Code:LAB30Order Name:Phenobarbital Level
Synonyms:Also see Free Phenobarbital (FPHENO, LAB3482)
Methodology:Turbidmetric rate
GH: Homogenous enzyme immunoassay
SJO/SJN: Chemiluminescent microparticle immunoassay (CMIA)
CPT Codes: 80184 x1
Turnaround Time:Performed and reported 24 h/day.

Collection Instructions

Optimal Volume:2.5 mL
Minimum\Peds Volume:0.8 mL
Container:Red (no gel), St Johns/St Joseph/Woodwinds-Green (lithium heparin, no gel)
Alternate Containers: Green (lithium heparin, no gel), Grand Itasca - Green (lithium heparin, no gel), St Johns/St Joseph/Woodwinds - Red (no gel)
Collection Instructions:Trough level is preferred; collect immediately before dose. It is advisable to monitor at the same time in the dosing schedule.
Causes for Rejection:Collection in a gel tube.

Processing and Shipping

Specimen Processing:Centrifuge and aliquot 1.25 mL, 0.3 mL minimum. Store in room temperature up to 48 hours. Alternatively, refrigerate.
Shipping Instructions:Ship at room temperature to arrive within 48 hours. Alternatively, ship at refrigerated temperature.
Stability:Stability: Room temperature - 48 hours; refrigerated - 1 month; frozen - 3 months.
Test Performed at or Referral Lab Chemistry  (Range, UMMC-West Bank, UMMC-East Bank, Southdale, Grand Itasca, St. Joseph's)


Critical Range:Greater than 50 mg/L
Therapeutic Range:15-40 mg/L
Grand Itasca: 10-40 ug/mL
Use:Monitor therapeutic drug level of phenobarbital; use with primidone levels to monitor therapeutic drug level of primidone; evaluate phenobarbital toxicity. Half-life is 50-120 h (adult); and 40-70 h (child).

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