Analysis of testosterone in serum using mass spectrometry

Area of Science:

• Analytical Chemistry
• Biochemistry
• Endocrinology

Background:

• Accurate testosterone measurement is crucial for diagnosing various endocrine disorders.
• Existing methods may suffer from interferences or lack sufficient sensitivity and precision.
• Development of robust and validated assays is essential for clinical diagnostics.

Purpose of the Study:

• To develop and validate precise and accurate analytical methods for testosterone quantification.
• To compare the performance of gas chromatography mass spectrometry (GC-MS) and liquid chromatography tandem mass spectrometry (LC-MS-MS) for testosterone analysis.
• To establish reliable methods for measuring testosterone levels in human serum.

Main Methods:

• Liquid-liquid extraction followed by derivatization for GC-MS analysis.
• Direct injection onto a C18 column for LC-MS-MS analysis.
• Use of deuterium-labeled internal standards (e.g., testosterone-16,16,17-d3) for both methods.
• Quantification using selected ion monitoring (GC-MS) and multiple reaction monitoring (LC-MS-MS).

Main Results:

• Both GC-MS and LC-MS-MS methods demonstrated high precision and accuracy, with run-to-run variability generally less than 6%.
• The methods exhibited linearity over a wide range, from 5 to 2000 ng/dL.
• No significant interferences were observed from common steroids typically found in human serum.

Conclusions:

• Validated GC-MS and LC-MS-MS methods provide accurate and precise quantification of testosterone in human serum.
• These methods are suitable for routine clinical laboratory analysis due to their reliability and wide linear range.
• The absence of interferences ensures the specificity of the testosterone measurements.