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HelpTest Code THEOX or LAB35 Theophylline Level, Serum or Plasma
Specimen Requirements
| Container Type: |
Optimal: Gold or Mint* *For STAT requests |
|
Acceptable: Red or Green |
|
| Optimal Collection Volume: |
4.5mL; full tube |
| Minimum Volume: |
|
| Collection Instructions: |
Gently invert the sample 5-6 times after collection. |
| Specimen Transport: |
Refrigerate |
| Processing Instructions: |
1. If serum, allow the specimen to clot for 30 minutes. 2. Centrifuge specimen within 2 hours of collection. 3. After centrifugation, specimen tubes without a gel barrier should have the serum or plasma aliquoted to a false bottom container. 4. Keep the serum or plasma refrigerated until testing can be performed. |
Specimen Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum* | Refrigerated | 7 days |
| Room Temperature | 1 day | |
| Frozen | 2 months |
*Note: Heparinized plasma in gel separator tubes is less stable than serum and is only suitable for add-on testing up to 2 days following sample collection.
Specimen Rejection Criteria
| Hemolysis | Mild OK; Moderate OK; Gross Reject |
| Lipemia | Mild OK; Moderate OK; Gross Reject |
| Icterus | Mild OK; Moderate OK; Gross Reject |
| Other | Quantity not sufficient |
Useful For
Monitoring therapeutic concentrations of Theophylline.
Methodology
Roche Cobas - Kinetic interaction of microparticles in solution (KIMS)
Reference Ranges
Therapeutic range: 10-20 ug/mL
Critical Value: > 25 ug/mL
Interpretive
Some patients may require serum or plasma levels outside these ranges for effective treatment. For diagnostic purposes, theophylline results should always be assessed in conjunction with the patient’s medical history, clinical examinations, and other findings.
Day(s) Performed
24/7
Expected TAT
Same day
Performing Laboratory
Bronson Laboratory, Chemistry - Kalamazoo
Sample Retention Time
7 days
CPT Code
80198
LOINC Code
4049-3