Conclusion
We found that the non-Gaussian distribution of BST in healthy population could be explained by a two population model in agreement with a previous work5,6. A great majority has a median BST at 5.0 µg/L and a 95th percentile at 8 µg/L. We thus propose to adopt a new threshold at 8µg/L and to suspect BST above 8µg/L as being part of the minority of healthy people with gene duplication and potentially HαT, to be confirmed by genetic analysis according to the eventual symptoms. This threshold is lower in teenagers (5.5 µg/L) and slightly higher above the age of 70 (8.5 µg/L). In addition, we describe that a small minority of HD have an apparent defect in basal tryptase production that needs to be explored genetically.