American Association of Critical-Care Nurses (AACN) Certification Practice Test

What is the normal range for creatine kinase (CK) levels?

1. 20-80 U/L

2. 30-190 U/L

3. 190-300 U/L

4. 300-400 U/L

The correct answer is: 30-190 U/L

The normal range for creatine kinase (CK) levels typically falls between 30 and 190 U/L. This enzyme is found primarily in heart and skeletal muscle, and it plays an essential role in energy production. Measurement of CK levels is often used in clinical settings to assess muscle damage, including conditions like myocardial infarction or rhabdomyolysis. Understanding normal CK levels is vital for interpreting laboratory results accurately. Values below or above this range can indicate various medical conditions. For instance, elevated CK levels may suggest muscle injury, while levels significantly lower than the normal range can sometimes occur without direct clinical relevance but may indicate poor muscle mass or other underlying issues. Having a firm grasp of the normal limits of CK levels is crucial for healthcare professionals, as it aids them in making informed clinical decisions and providing appropriate care for patients presenting with related symptoms.