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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Theophylline

Test Code(s): THEO

CPT Code(s): 80198

Methodology: Particle Enhanced Turbidometric Inhibition Immunoassay (PETINIA)

Clinical Significance: Bronchodilator

Days Performed: Daily, 24 hours.

Turnaround Time: Stat: 1 hour.
Routine: 4 hours.


Specimen Requirements

Specimen: Blood

Collection Instructions: Collect specimen for trough level within 60 minutes of next dose. If drug is given IV, collect specimen for peak level 4 - 6 hours after the initiation of infusion. Subsequent levels should be drawn at 24 hour intervals. If drug is given PO (plain tablet or solution), collect specimen for peak level 2 hours after dose. If Theo Dur is given, collect peak specimen 4 hours after dose.

Collection Container: Preferred: Red top
Also Acceptable: Green top (with lithium heparin anticoagulant)

Collection Volume: Preferred: 2 mL
Pediatrics: 0.4 mL

Sample Analyzed: Serum or plasma

Volume Required: Preferred: 1 mL
Pediatrics: 0.2 mL

Specimen Processing: Centrifuge.  Transfer cell-free serum or plasma 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) or green top with yellow ring (PST) tubes are not acceptable.


Interpretation

Generally effective therapeutic concentration:

30 days and up: 5-15 mcg/mL

 

Toxic: > 20 mcg/mL

Critical Calls: View

Additional Information:

Result of "BELOW" indicates that the concentration is below the method detection limit of 2.0 mcg/mL. The half-life of theophylline in adults is approximately 3-8 hours. In children the half-life is 1-8 hours and in newborns, 17-45 hours. The half-life in adults can be shorter for smokers. The peak concentration in serum/plasma for adults is reached in 2-3 hours and for newborns in about 2 hours, but this is variable.

Theo-Dur Aminophylline

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