LC-ESI-MS/MS quantification of 4β-hydroxycholesterol and cholesterol in plasma samples of limited volume

- An assay was qualified for quantification of 4β-hydroxycholesterol and cholesterol.
- This assay was based on isotope-dilution, surrogate matrix and LC-ESI-MS/MS.
- The assay used only 5-μL sample and has acceptable sensitivity and reproducibility.
- Assay was validated by incurred sample reanalysis and cholesterol enzymatic method.
- Both analytes were quantified in plasma from human, naïve and FRG chimeric mice.