Blood methods

Proteins absolutely quantified by targeted MS

Mass spectrometry-based targeted proteomics using the DiscoveryEdge175 panel (ProteomEdge AB) was applied to a longitudinal pregnancy cohort. DiscoveryEdge175 is a panel of pre-aliquoted and dried heavy labeled internal standards, engineered for high-throughput, multiplex quantification of blood plasma proteins by mass spectrometry. It comprises of isotope-labelled protein standards termed Quantitative Recombinant Protein Standards (qRePS) enabling seamless absolute quantification of up to 176 plasma proteins including complement factors, coagulation markers and apolipoproteins. The cohort comprised serial plasma samples collected from pregnant women in each trimester (first, second and third) to capture dynamic proteome changes over gestation. Measurements were performed using Evosep One (Evosep) coupled to Stellar Mass Spectrometer (ThermoFisher Scientific) LC–MS/MS at 40SPD with scheduled acquisition.

To explore protein dynamics during pregnancy, protein concentrations were compared across the three trimesters. The 99 proteins detected revealed distinct patterns with some proteins increased progressively with gestational age, others remained stable, while a subset decreased over time. The measurements demonstrated high analytical reproducibility, with a median coefficient of variation of 7.5%, achieved without any batch normalization.