Circulating choline and phosphocholine measurement by a hydrophilic interaction liquid chromatography–tandem mass spectrometry

BACKGROUND: Given the growing interest in studying the role of choline and phosphocholine in the development and progression of tumor pathology, in this study we describe the development and validation of a fast and robust method for the simultaneous analysis of choline and phosphocholine in human plasma. METHODS: Choline and phosphocholine quantification in human plasma was obtained using a hydrophilic interaction liquid chromatography–tandem mass spectrometry technique. Assay performance parameters were evaluated using EMA guidelines. RESULTS: Calibration curve ranged from 0.60 to 38.40 μmol/L (R(2) = 0.999) and 0.08–5.43 μmol/L (R(2) = 0.998) for choline and phosphocholine, respectively. The Limit Of Detection of the method was 0.06 μmol/L for choline and 0.04 μmol/L for phosphocholine. The coefficient of variation range for intra-assay precision is 2.2–4.1 % (choline) and 3.2–15 % (phosphocholine), and the inter-assay precision range is < 1–6.5 % (choline) and 6.2–20 % (phosphocholine). The accuracy of the method was below the ±20 % benchmarks at all the metabolites concentration levels. In-house plasma pool of apparently healthy adults was tested, and a mean concentration of 15.97 μmol/L for Choline and 0.34 μmol/L for Phosphocholine was quantified. CONCLUSIONS: The developed method shows good reliability in quantifying Choline and Phosphocholine in human plasma for clinical purposes.