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Feb 8, 2018

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Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Toxicology

Theophylline

Theophylline (THEO) Toxicology Lab Test

Name: Theophylline

Test Name: Theophylline

Health Link Test Code: THEO

LIS Test Code: THEO

CPT Code(s): 80198

Methodology: Enzyme Immunoassay

Clinical Information:

Bronchodilator

Days Performed: Daily, 24 hours.

In-Lab Turnaround Time: 4 hours.

Stat In-Lab Turnaround Time: 1 hour.

Specimen: Blood

Collection Container: Red top

Also Acceptable: Green top (with lithium heparin anticoagulant)

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 Volume: 2 mL

Pediatric Collection Volume: 0.4 mL

Stability Refridgerated:

3 months

Stability Frozen:

3 months

Sample Analyzed: Serum or plasma

Testing Volume: 1 mL

Pediatric Testing Volume: 0.2 mL

Specimen Processing:

Centrifuge. Transfer cell-free serum or plasma to plastic vial. Refrigerate.

Specimen Transport:

Transport specimen to the laboratory. Transport with coolant pack if coming from clinic 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:

10.0-20.0 ug/mL

 

Toxic: > 20 ug/mL

 

Apneic spells in neonates: 5.0-10.0 ug/mL

Effective Date of Reference Range: Mon, 10 Aug 2015 00:00:00 CDT

Critical Calls: yes

Additional Information:

Result of "BELOW" indicates that the concentration is below the method detection limit of 2.0 ug/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.