Abstract
We characterized the distribution of cardiac troponin I (cTnI) levels determined using a newly developed, highly sensitive assay reagent, and examined the relationship between blood cTnI levels and medical checkup items of examinees in our hospital.
Among the 283 participants in the study, the number of those with cTnI equal to or below the background level (zero concentration) was 279 when measured by the conventional method, while 9 when measured by the highly sensitive method. cTnI levels were significantly higher in males and positively associated with the age. The multiple regression analysis revealed that male sex and age were independent factors for increased cTnI levels.
When the participants were classified into “non-healthy subjects” and “healthy subjects” according to criteria based on personal medical history, present illness and laboratory test values, 166 participants (94 males and 72 females) were classified into healthy subjects and 117 participants into non-healthy subjects. About 70% of the 117 non-healthy subjects met criteria of hypertension and/or dyslipidemia. cTnI levels were significantly higher in the non-healthy subjects than in the healthy subjects. In addition, non-healthy subjects with hypertension, declined kidney function, or dyslipidemia showed significant high blood cTnI levels.
In conclusion, the highly sensitive assay system can measure low blood cTnI levels in medical checkup examinees, suggesting that it can detect slight myocardial changes associated with cardiomyopathy. The blood cTnI reference value as myocardial markers should be set considering gender and age.
