Patent ID: 9746464
Date: 2017-08-29
CPC Classifications: C12Q,G01N,Y10T

Claim:
1. A method for quantifying the amount of an unlabeled analyte in a biological sample, comprising: measuring the amount of the unlabeled analyte and two or more stable-isotopically labeled versions of said analyte in said biological sample by mass spectrometry, wherein said two or more stable-isotopically labeled versions of said unlabeled analyte are present at different known concentration levels from each other and have isotopic masses that differ from each other and from the mass of the unlabeled analyte in a manner that can be distinguished by a mass spectrometer, either through direct measurement of molecular mass or through mass measurement of fragments, wherein measurement of the known amount of said two or more stable-isotopically labeled versions of the analyte provides an internal standard curve and wherein the amount of said unlabeled analyte in said sample is calculated by comparison to said standard curve.