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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Pentobarbital

Test Code(s): PENT / HCPENT

CPT Code(s): 80345

Methodology: Gas Chromatography

Clinical Significance: Hypnotic, sedative

Days Performed: Daily, dayshift- Pathology Resident approval is required after hours.

Turnaround Time: Stat: 3 hours.
Routine: 24 hours.

Specimen Requirements

Specimen: Blood

Collection Container: Preferred: Red top

Collection Volume: Preferred: 3 mL
Pediatrics: 1 mL

Sample Analyzed: Serum

Volume Required: Preferred: 1 mL
Pediatrics: 0.4 mL

Specimen Processing: Centrifuge. Transfer cell-free serum to plastic vial. Refrigerate.

Specimen Transport: Transport specimen to UWHC Core Laboratory (B4/220). Transport with coolant pack if coming from outreach location.

Unacceptable Criteria: Specimens collected in red cap with yellow ring (SST) tubes are not acceptable.

Stability: Ambient: 14 days
Refrigerated: 14 days
Frozen: 14 days


Interpretive Guidelines:

Generally effective therapeutic concentration when used in treatment of increased intracranial pressure:


18 years and up: 2.5 - 4.0 mg/dL


All results greater than 3.0 mg/dL are considered critical and will be called to the ordering source. 


NOTE: When thiopental is administered all pentobarbital results >1 mg/dL are considered critical and will be called to the ordering source.



Critical Calls: View

Additional Information:

Result of "BELOW" indicates that the result is below the method detection limit of 0.2 mg/dL. The half-life is 15-48 hours. Peak serum concentration is usually reached 0.5-2 hours after a single oral dose.


This test was developed and its performance characteristics determined by the UWHC Clinical Laboratories.  This test meets the standards for clinical testing.  This test should not be regarded as investigational or for research use.  The US Food and Drug Administration (FDA) has not approved or cleared this test; however, the FDA has determined that such clearance or approval is not necessary.


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