Theophylline (Serum/Plasma Mass Concentration)
This test measures the amount of theophylline, a medication used to treat breathing problems like asthma or chronic obstructive pulmonary disease (COPD). It helps doctors monitor your dose to ensure it’s effective without causing too much side effects.
["This test helps adjust your medication to keep it at safe, effective levels."]
Key facts at a glance
- LOINC
- 80967-3
- Short code
- Theophylline free SerPl-mCnc
- Synonyms
- Theophylline free SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 20
- Critical range
- — – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order this test if you’re taking theophylline (a bronchodilator) to manage breathing issues. Regular monitoring helps prevent side effects like rapid heart rate, nausea, or insomnia by ensuring your dose stays within a safe range.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample (either serum or plasma) via a simple venipuncture. If you’re on a diet or have taken certain medications recently, let your doctor know—it may affect results.
What the Results Mean
Results show your current theophylline level. While exact ranges vary by lab and patient, levels are typically checked to avoid toxicity or insufficient effectiveness. Your doctor will interpret these results in the context of your symptoms and medication.
Possible Side Effects of Theophylline
High levels can cause side effects like headaches, dizziness, or irregular heartbeat. Low levels may mean your medication isn’t working well. Always follow your doctor’s guidance on timing and dosage.
Reference range
Therapeutic: 10-20 mcg/mLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Monitoring for Safety and Effectiveness
Short name
Theophylline Level
Frequently asked questions
Why is this test important for my health?
What if my test results are out of range?
Can diet or other medications affect this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy