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Test Code THEO Theophylline

Laboratory Code

LAB35

Specimen Requirements

Submit only one of the following:
 

Preferred
Specimen Type: Serum
Container/Tube: Gold Top (SSTII)
Volume: 5.0 mL 
Minimum Volume: 0.5 mL
Collection Instructions: Allow specimen to clot for 30 mins and centrifuge within 2 hrs.


Acceptable
Specimen Type: Plasma
Container/Tube: Green Top (Li Heparin/PST)
Volume: 4.5 mL
Minimum Volume: 0.5 mL plasma
Collection Instructions: Centrifuge within 2 hrs.

Specimen Stability

Specimen Type Serum/Plasma
Ambient Not available
Refrigerate 3 months
Frozen 3 months

Methodology

Enzyme Immunoassay

Days and Times Performed

24 hrs, TAT 1 day

Specimen Condition

Haemolysis OK
Icterus OK
Gross Lipaemia Alert/Reject
Others Not applicable

Reference Interval

Therapeutic range 10 – 20 mg/L
Critical value  > 20 mg/L

Testing Laboratory

National University Hospital

Clinical Chemistry, 67724346

Useful For

Therapeutic drug monitoring.

Service Code

31831

LOINC Code Information

4049-3

Update

Last updated 13/03/2025