Theophylline Level (Mass Concentration)

Why This Test Is Done

Doctors may order a theophylline test if you’re taking medications containing theophylline (such as aminophylline or theophylline itself) to manage conditions like asthma, chronic obstructive pulmonary disease (COPD), or other breathing-related issues. It helps prevent dangerous levels of the medication that could cause side effects or health risks.

What to Expect Before the Test

No special preparation is needed for this test. You may have a small needle inserted into a vein in your arm, or a blood sample may be collected from a finger prick. If you’re on a regular medication schedule, let your healthcare provider know to ensure timing aligns with your usual dose.

What the Test Results Mean

Theophylline levels are measured in micrograms per milliliter (mcg/mL). Results help determine if your dose is too high or too low. High levels may cause nausea, rapid heart rate, or other symptoms, while low levels might mean your medication isn’t working effectively.

Possible Side Effects or Risks

While rare, very high theophylline levels can lead to serious side effects like seizures, irregular heartbeat, or even heart failure. Your doctor will adjust your medication based on these results to keep you safe.