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THEOPHYLLINE, serum (087-0374)
Test Mnemonic:


Specimen Requirements:

Routine venipuncture. The usual sampling times for intravenous dosing are: Trough - prior to intravenous infusion; Peak - 30 minutes after completion of leading dose; or at timed intervals to evaluate therapy. For oral dosing, the usual sampling times are: Peak - 2 hours after rapid release product or 4 hours after sustained release product; Trough - immediately before next dose.  Collect 7mL of blood in  Red-topped tube. (Min.: 3mL of blood).

DO NOT draw blood in SST/gel separator vacutainer tube.


Delivered to Sample Management within 2 hours of collection.

Specimen Preparation:

Allow specimen to clot completely at room temperature. Centrifuge to separate serum from cells within 2 hours of collection. Transfer serum from red-topped tube to labeled plastic transport tube. 


Room Temperature for ≤7 days, Refrigerated for ≤7 days, Frozen for ≤60 days. (Avoid repeated freeze/thaw cycles).

Causes for Rejection:

Blood drawn in SST/gel separator vacutainer tube, incomplete and/or incorrect sample identification, improper storage/transport, gross hemolysis, icterus or lipemia.                                                           

Reference Range:

By report (reports may vary based on instrumentation, patient age and sex)

Turnaround Time:

Routine: 8 hours, ASAP: 4 hours; STAT: 1 hour


Rate Two Point


Clinical Chemistry

CPT 4 Code:


When ordering tests for which Medicare or Medicaid reimbursement will be sought, physicians should only order tests that are medically necessary for the diagnosis or treatment of the patient. Components of the organ or disease panels may be ordered individually. The diagnostic information must substantiate all tests ordered and must be in the form of an ICD-10 code or its verbal equivalent.
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