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• Creatine kinase is also called creatine phosphokinase
• Creatine kinase

  • releases its phosphates to give ADP so it can be used in muscle contraction; way to store phosphates for a short period of time to make ADP into ATP 
• Monomers that make up creatine kinase:

  • “M” monomer mostly found in muscle
  • “B” monomer mostly found in brain tissue
• elevation of CK type indicates damage to that area
• normal levels of CK-BB may not be detectable
• non-pathological increases of CK-MM include strenuous exercise
• total CK above 100 IU reflexes CK-MB
• screening for total CK values is enzymatic or kinetic
• CK-MB immunoassay is an isoenzyme test and is measured in a unit other than IU
• a better diagnostic tool for MI is troponin, the best diagnostic tool is an EKG
• newer information uses absolute measurement of CK-MB by immunoassay
• CK-MB may be a good indicator to detect whether pt has had second MI
• mitochondrial CK is CK-MT or CK-Mi
• CK-Mt is not normally detectable, and may seem to be an indicator of severe disease
• 2 accepted meanings of macro-CK

  Ig complex and Oligomeric Ck-Mt
• type 1 Macro-Ck elevations has no clinical significance
• separation of Creatine Kinase from slowest to fastest is CK-Mt, Ck-MM, macro-CK, CK-MB, CK-BB
• CK-MB quantitation is done via immunoassay

  • reported in nanograms/mL or % of total
• absolute values of CK is laboratory dependent
• lactate dehydrogenase aka LD or LDH
• lactate dehydrogenase functions in the interconversion of lactic and pyruvic acids
• structure of lactate dehydrogenase: tetramer with combinations of H and M types 
• Differentiation of LDH isoenzymes can be done by electrophoresis
• • LD6: alcohol dehydrogenase
  • Slowest on electrophoresis