Markers Of Muscle Damage

Question 1

List four characteristics of an ideal biomarker

Answer 1

1. High sensitivity
2. High specificity
3. Analytically:
   → cost effective
   → quick
   → accurate
4. Clinically:
   → ability to influence therapy & improve outcome
   → prognostic

Question 2

Graph depicting biomarker changes following cardiac muscle damage

Answer 2

Question 3

Explain why CK-MM is a suitable marker to identify early skeletal muscle damage

Answer 3

1. A biomarker is a measurable substance or parameterindicating an underlying biochemical or pathological process
2. Talk about ideal biomarker features
3. Skeletal muscle can be damaged due to excess exercise stress, rhabdomyolysis etc.
4. Creatine kinase is mostly found in cytoplasm which permits easy release in damage
5. CK has 3 isoforms : CK-BB (brain); CK-MB (cardiac muscle); CK-MM (skeletal muscle)
6. CK-MM is predominantly in skeletal muscle, giving rise to high specificity as a feature of a biomarker
7. Half-life is also considerably longer than that of myoglobin so that is prevalent in blood longer, making it easy for screening
8. Rapid release and high sensitivity makes CK-MM a suitable biomarker to identify early muscle damage