Abstract 12265: Is hs-TnT Cut-off Level for Acute Coronary Syndromes Age Dependent?
Background: introduction of hs-Tn assays has led to a greater sensitivity for the diagnosis of ACS at the cost of a reduction in specificity. As levels of hsTnT increase with age, it has been postulated that the use of the same cut-off for all ages might not be appropriate and that better specificity could be achieved using a different cut-off for aged people.
Methods: 452 pts with chest pain were enrolled in the Emergency Department . We divided the whole population in quartiles according to age (1° quartile 18-50 years, 2°quartile 51-63 years. 3° quartile 64-75 years, 4° quartile 76-90 years). In all pts hsTnT was determined.
Aim: We sought to determine which level of hs-TnT is associated with the best sensitivity (SE) and specificity (SP) in each age group and whether this approach is superior to the current use of a single cut-off for all ages..
Results: 60 out of 452 pts were discharged from the hospital with a diagnosis of ACS (13%). Using the currently recommended cut- off of 14 pg/ml (manufacturer) in the 1st quartile AUC was 0.730, (SE 0.50, SP 0.97); in the 2nd quartile AUC was 0.705, (SE 0.53, SP 0.89); in the 3rd quartile AUC was 0.853, (SE 0.90, SP 0.80), in the 4th quartile AUC was 0.662, (SE 0.9, SP 0.43). Conversely, analysing the population according to the best cut-off for age (BCO) , in the 1st quartile BCO was 159.59 pg/ml (AUC 0.64, SE 0.5, SP 0.99). In the 2nd quartile BCO was 9.44 pg/ml (AUC 0.82, SE 074, SP 0.81). In the 3rd quartile BCO was 13.44 pg/ml (AUC 0.91, SE 0.95, SP 0.81). In the 4th quartile BCO was 38.7 pg/ml (AUC 0.88, SE 0.84, SP 0.86). No significant differences were found between the first three quartiles, but a highly significant improvement in diagnostic accuracy (p<0.0001) was observed in the fourth quartile using the BCO.
Conclusions: Our results suggest that the recommended cut-off for hs-TnT (14 pg/ml) is appropriate only in the population aged up to 75 years and that in older people a higher cut-off should be used to obtain a greater diagnostic accuracy.
- © 2012 by American Heart Association, Inc.