Because the 99th percentile is of such importance in defining myocardial injury and myocardial infarction, it is important to know whether there are real age-related differences in troponin 99th percentiles.We went to our database from the Canberra Heart Study where 1062 apparently healthy subjects were extensively screened for occult cardiac disease, and looking at persons aged65 years and65 years, for men and women separately, we compared a variety of cutpoints from the 99th percentile down to the 50th percentile.With our rigorous criteria for defining cardiac health, we excluded 67.2% of males aged65 years and 53.8% of women aged 65 years and older. Even with these rigorous exclusions we found that at every cutpoint examined between the 99th percentile and the 50th percentile, persons aged65 years had lower troponin I concentrations that persons aged 65 years and older. Similarly, at every cutpoint examined, women had lower troponin I concentrations than did men. For the 4 separate groups examined (men and women, age 65 years and 65 years and older) after the exclusions of persons with subclinical cardiac disease, the distributions were not significantly different to a Gaussian distribution.With the rigorous exclusions of persons with subclinical cardiac disease, and the fact that our populations have a Gaussian distribution, our data suggests that age-related hs-cTnI concentrations are real. This has important implications particularly when assessing older persons in the Emergency Department.
