Objective: To develop a high resolution mass spectrometry (HRMS) method to quantify levonorgestrel (LNG) in serum.
Study design: Levonorgestrel was extracted using solid phase extraction and measured using liquid chromatography (LC) HRMS.
Results: Low limit of quantification (LLOQ) was 25 pg/mL and low limit of detection (LLOD) was 12.5 pg/mL. Precision and accuracy bias were <10%. LNG in serum samples from Mirena® users ranged between 37 to 219 pg/mL (n=12). In eight out of 22 patients with suspected intrauterine device (IUD) expulsion LNG was detected (26-1272 pg/mL).
Conclusion: A sensitive, fast and simple LC-HRMS method was developed to detect trace levels of LNG.
Keywords: High resolution mass spectrometry; Intrauterine device; Liquid chromatography; Lower limit of quantification; Solid phase extraction.
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