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Caffeine
Test Code305
CPT Codes
80155
Preferred Specimen
1 mL serum collected in a red-top tube (no gel)
Patient Preparation
Collect as a trough just prior to next dose
Minimum Volume
0.2 mL
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 5 days
Refrigerated: 7 days
Frozen: Unacceptable
Refrigerated: 7 days
Frozen: Unacceptable
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Serum separator tube (SST)
Methodology
Immunoassay (IA)
Setup Schedule
Set up: Mon-Sat; Report available: 1-2 days
Reference Range
8.0-20.0 mg/L
Clinical Significance
Coffee, tea and other beverages may contain caffeine. Caffeine is a methylxanthine found in over the counter products and in prescription medications. Small premature infants with mild respiratory distress shortly after birth may be treated with theophylline or caffeine. In neonates, a significant amount of theophylline is converted to caffeine. Since the demethylation pathway of theophylline is relatively undeveloped, caffeine levels may be elevated. Caffeine clearance rates typically reach adult values at about 3-4 months of age.
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153