The Tenormin (or Atenolol) test is used to determine the levels of this drug in the blood serum. Atenolol is a commonly used beta-blocker for treating high blood pressure and angina, as well as for preventing heart attacks. The purpose of this test is to assess the effectiveness of the treatment and ensure that the drug levels in the blood remain within the appropriate therapeutic range. Test results can help doctors adjust the dosage if necessary, contributing to better management of the patient's health and reducing the risks associated with the treatment. The test is usually performed after starting the treatment to evaluate the patient's response and may also be used in certain cases to avoid potential side effects.