In reading the article by Lopes-Virella et al. (1), we were rather concerned that the authors referred to “creatinine kinase” as a marker of cardiac injury. We are certain that the authors wanted to refer to creatine kinase, which is usually abbreviated as CK, and not “creatinine kinase,” as such an enzyme does not exist. Creatine kinase catalyzes the reversible phosphorylation of creatine to phosphorylcreatine, whereas the conversion of creatine to creatinine requires no enzymatic input.
A Medline search performed on 24 April 2004 for the incorrect term “creatinine kinase” revealed a total of 356 entries. Organizing these entries according to which decade they were published, we could see that from 1964 to 1974 there were 2 entries, from 1974 to 1984 there were 20 entries, from 1984 to 1994 there were 128 entries, and finally (rather worryingly) from 1994 to 2004 there were 206 entries. It evident that the number of entries for the incorrect term “creatinine kinase” has been steadily increasing. We are deeply concerned about this unjustified increase and wish to make more authors aware of the correct terminology.
