Inadequate Attempts to Measure the Microheterogeneity of Transthyretin by Low-Resolution Mass Spectrometry (Letters) (Letter to the Editor‪)‬

To the Editor: Recently, the authors of 2 studies have claimed to measure accurately the microheterogeneity of transthyretin (TTR) variants by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) immunoassays (1, 2). Here we report that the mass spectrometric performance in those studies was not adequate to measure the respective TTR variants.