Test Name: Theophylline
Health Link Test Code: THEO
LIS Test Code: THEO
CPT Code(s): 80198
Methodology: Enzyme Immunoassay
Days Performed: Daily, 24 hours.
In-Lab Turnaround Time: 4 hours.
Stat In-Lab Turnaround Time: 1 hour.
Collection Container: Red top
Also Acceptable: Green top (with lithium heparin anticoagulant)
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
Sample Analyzed: Serum or plasma
Testing Volume: 1 mL
Pediatric Testing Volume: 0.2 mL
Centrifuge. Transfer cell-free serum or plasma to plastic vial. Refrigerate.
Transport specimen to the laboratory. Transport with coolant pack if coming from clinic location.
Specimens collected in red cap with yellow ring (SST) or green top with yellow ring (PST) tubes are not acceptable.
Generally effective therapeutic concentration:
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
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.