At a Glance
Why Get Tested?
To determine the concentration of theophylline or caffeine in the blood to establish an appropriate dose and to maintain a therapeutic level
When to Get Tested?
At the start of drug therapy and at regular intervals to monitor the drug's concentration; when indicated, to detect low or excessive (potentially toxic) concentrations
A blood sample drawn from a vein in your arm or from pricking an infant's heel
Test Preparation Needed?