The present invention relates to a method for determining, predicting or estimating the biological age of a subject, or for providing a measurement for use in determining, predicting or estimating the biological age of a subject or for predicting the presence or absence of at least one disease in a subject, predicting the risk of a subject of having or developing at least one disease; and/or predicting the risk of mortality of a subject. This invention also relates to a device for determining the presence and/or amount of each biomarker in a set of biomarkers; a set of probes for determining the presence or amount of a set of biomarkers, and the use of such device and/or probes in any of the above methods. Also provided is a biomarker testing kit for use in a method as described herein and a computer-readable storage medium or a computer program comprising computer-executable instructions and associated method.

The present disclosure provides a method of assessing translation efficacy of an mRNA using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The mRNA is first translated into protein either in a cell lysate (cell-free translation; CFT) or inside a cell (cell-based translation; CBT) and analyzed using LC-MS/MS. The method provides advantages such as speed and convenience over traditional immunoassay-based methods of detecting translated proteins. Translation using CBT may be necessary in certain formulations of the mRNA, such as when the mRNA or a mixture of mRNAs is encapsulated inside a lipid nanoparticle.