Objective: Activities of total creatine kinase and its isoform creatine kin
ase are usually significantly elevated in patients with myocardial or skele
tal muscle injury as well as in those with renal failure. The purpose of th
is study was to compare findings for creatine kinase mass, cardiac troponin
T and cardiac troponin I with those of creatine kinase and creatine kinase
MB activity.
Methods: Blood samples fi om 118 patients: were studied. Fifty eight patien
ts had significantly elevated creatine kinase activity (39 with and 19 with
out clinically proven myocardial injury or infarction) and 60 were normal c
ontrols. The sensitivity, specificity, positive and negative predictive val
ues were calculated for all markers.
Results: Cardiac troponins had 100% sensitivity and negative predictive val
ue, for myocardial injury, as compared with 92% and 96% for creatine kinase
activity and 96% and 97% for creatine kinase-mass. Cardiac TnI had the hig
hest specificty and positive predictive value (99% and 98%) as compared wit
h cardiac troponin T (96% and 93%), creatine kinase-mass (92% and 86%) and
creatine kinase activity (89% and 80%).
Conclusion: Cardiac troponins, especially cardiac troponin T, have very hig
h sensitivity, specificity and predictive value for myocardial injury.