The comparison of serum T and free-T with Sal-T (LC-MS/MS) for both males and females is shown in Figure 4. Two outliers were excluded from the analysis because there was insufficient sample to repeat the test. Sal T analysisThe LC-MS/MS method for measuring Sal-T in males has previously been shown to have good analytical performance (13).
You shouldn’t try to self-diagnose a testosterone issue. Pharmacies and various companies may sell at-home testosterone tests. An abnormal testosterone test result doesn’t guarantee that you have a medical condition.
The concentration versus the area ratios between Amplifex Keto-testosterone (analyte) and Amplifex Keto-13C3-testosterone (IS) was used for the linear regression analysis. Prepared samples (prepared using either individual vials or 96-well filter plate method) were analyzed on the Topaz IVD LC-MS/MS System (4500MD Mass Spectrometer). A total of 140 µL of the supernatant was then transferred to an autosampler vial (polypropylene with 300 µL insert) for LC-MS/MS analysis. To correct for any variability in sample preparation and analysis, a methanol solution of 2,3,4-13C3-testosterone (20 ng/mL, prepared by diluting the 10 µg/mL certified standard) was used as an IS. Pediatric plasma (lithium heparin (LH), K2EDTA)/serum matched samples were purchased from iSpecimen (Lexington, MA).
Ion suppression is a matrix effect which occurs when compounds in a sample compete with the analyte for ionisation in the source. Department of Health and Human Services Food and Drug Administration (15) which include acceptance criteria for linearity, precision, recovery and sample stability. The assay was validated according to the published Bioanalytical Method Validation guidelines issued by the U.S. Transitions were monitored in multiple reaction monitoring mode, with a dwell time of 0.15 s, the capillary was maintained at 0.8 kV and the desolvation temperature and gas flow were 650°C and 700 L/h respectively. The signal was optimized for the testosterone and D5-testosterone precursor ions (seen at m/z 289.3 and m/z 294.2) and the most abundant product ions (seen at m/z 109.2 and m/z 97.15 for testosterone and at m/z 100.2 for D5-testosterone). The mass spectrometer was a Xevo TQ-S™ mass spectrometer (Waters Corporation, Manchester, UK) operated in positive ionization mode. The clear supernatant in each sample was either pooled for stability studies or divided into three equal aliquots for validation studies.
The aim of this study was the development of an analytical method for measuring total testosterone in sera from men, women and children. The testosterone QI/CI ratios of calibrators and of 56 serum samples from the same batch of the above accuracy testing experiment were compared. Sample matrix effects (ME) were evaluated on 6 different matrices including ethanol, saline, one time charcoal processed serum, six times charcoal processed serum, male serum and female serum as previously described 30,37. Frozen human serum samples and charcoal processed (one time or six times) sera were purchased from Bioreclamation (Hicksville, NY). However, studies comparing routine clinical mass spectrometric assays against a reference measurement procedure showed inter-method variability in precision and accuracy . This can be attributed in part to the higher specificity of this assay technology which is achieved by isolating the analyte from the sample matrix prior to analysis and by mass and structure-specific detection . Considerable inaccuracy of testosterone assays has been described, especially at testosterone concentrations commonly observed in women and children 10,21–25.
Essays, links, and short posts from Quantified Self participants on the culture, tools, and methods of self-tracking. We help you make discoveries using your own data. Most of the notebooks make pretty specific use of the Open Humans API at least for getting the data, but if people want to adapt them for local use we could offer that! Why is injection scheduled embedded rather than data? Could I download the notebook and and run it on my computer without ever uploading data?
Over the past decade, DBS sampling has been increasingly used for microsampling across various fields due to its significant advantages regarding ease of sample retrieval, shipment, and enhanced analyte stability . Hematocrit correction and matrix effect evaluations confirmed the robustness of the assay for clinical and research applications. The method showed high precision, with intra‐ and inter‐day coefficients of variation below 10%, and satisfactory recovery rates. Accurate testosterone measurement is essential for diagnosing endocrine disorders such as hypogonadism and polycystic ovary syndrome and for routine testing. Testosterone is a critical hormone involved in regulating various physiological processes in both men and women. This section collects any data citations, data availability statements, or supplementary materials included in this article. The authors would like to acknowledge Stefany Healy and Brian L. Williamson from the SCIEX Diagnostics team for writing the sample preparation robot script of plate shaking and centrifugation.
Unknown sample concentrations were measured based on the calibration curve generated with the calibrators described in section 2.2. The concentrations of the calibrators and controls are traceable to NIST 971, Standard Reference Material (SRM) of testosterone in human serum matrix. Analyte extraction and derivatization are performed simultaneously, and the incubation time during derivatization could also aid in improving the protein precipitation and testosterone extraction efficiency, as it is common practice to incubate the samples upon extraction .

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