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Test Code THEO Theophylline

Specimen and Container/Tube

Specimen Type: Serum

Preferred Specimen: Red Top

Other Acceptable specimens: Serum/Gold Top*, Plasma/Li or Sodium-Heparin Dark Green Top (No Gel Separator),Plasma/Lavendar K2 Top

*Gold top not suitable for add-on requests

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

  • Collect specimen per standard collection procedure and send to laboratory immediately. Specimens representing the trough level should be collected just before the next scheduled dose at steady state.

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Specimens representing the trough level should be collected just before the next scheduled dose at steady state.
  • Samples should be centrifuged within 2 hours of collection.
  • Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
  • Aliquot sample into plastic transport tube containing a minimum of 0.2 mL of specimen.
  • Samples must be sent refrigerated at 2-8oC.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that are clotted or grossly hemolyzed.
  • Specimens that were transported unspun/whole blood and draw time is greater than 6 hours.

Reference Values

Test

Age

Sex

Reference Range

Theophylline

All

All

10 - 20 μg/mL

Critical Values

Analyte

Unit

Low

High

Age

Theophylline

μg/mL

N/A

> 25

All

CPT Codes

80198

LOINC Codes

4049-3

Volume

Preferred Volume: 0.5 mL

Minimum Volume: 0.2 mL

Specimen Stability

Storage Temperature

Stability

Room temperature

N/A

Refrigerated

7 days

Frozen

60 days

Collection Instructions

Collect specimen per standard laboratory collection procedures. Specimens representing the trough level should be collected just before the next scheduled dose at steady state.

 

Test Components

Theophylline

Clinical Indications

  • Monitoring of theophylline concentrations in serum is useful, since rates of individual theophylline clearance can vary and severe toxicity has been observed without prior occurrence of minor side effects.

Methodology

Kinetic Interaction of Microparticles in solution (KIMS) (Roche Diagnostics)

Additional Information

  • Results should always be assessed in conjunction with patient's medical history, clinical examination and other findings.
  • Some therapeutic drug concentrations are reduced when the sample is stored in a seperator tube for a prolonged period of time (>2 hours).

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

 

STAT Turnaround Time: 1 hour

Routine Turnaround Time: 4 hours

Testing Schedule: 24/7

Last Review Date

1/26/23