Anyone know if there’s lab tests for ImP already? Is it a common or well known enough target?

Another paper describes how imidazole propionate serum levels were measured: https://www.nature.com/articles/s41467-020-19589-w

"""Imidazole propionate serum measurements

ImP was quantified using ultra-performance liquid chromatography coupled to tandem mass spectrometry according to previous work. Briefly, serum samples were extracted with 3 volumes of ice-cold acetonitrile containing internal standards (13C3-labeled ImP and urocanate). After derivatization to butyl esters using 5% hydrochloric acid in butanol, the samples were separated on a C18 column using a gradient consisting of water and acetonitrile. Quantification was made using an external calibration curve16."""

So yes, but no.

These are typically measured using liquid chromatography coupled to tandem mass spectrometry. That also gives the opportunity to measure thousands of other metabolites, and thus get a broader picture of health. Unfortunately, commercial B2C metabolomics is not there yet. It's mostly used in population genomics research.