From venipuncture to self-sampling DBS: a shift in monitoring testosterone levels

Anouk Olthof; Jacquelien Hillebrand; Deursen-Nagel Lysette van; Anita Boelen; Andreas Meiszner; Heijboer Annemieke C

doi:10.1530/endoabs.110.EP40

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Endocrine Abstracts (2025) 110 EP40 | DOI: 10.1530/endoabs.110.EP40

ECEESPE2025 ePoster Presentations Adrenal and Cardiovascular Endocrinology (170 abstracts)

From venipuncture to self-sampling DBS: a shift in monitoring testosterone levels

Anouk Olthof ^1,2 , Jacquelien Hillebrand ^1,2 , Lysette van Deursen-Nagel ³ , Anita Boelen ^2,4,5 , Andreas Meißner ^3,5,6 & Annemieke C Heijboer ^1,2,5

Author affiliations

¹Endocrine Laboratory, Department of Laboratory Medicine, Amsterdam UMC, University of Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, Netherlands; ²Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam, Netherlands; ³Department of Urology, Amsterdam UMC, location University of Amsterdam, Amsterdam, Netherlands; ⁴Endocrine Laboratory, Department of Laboratory Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands; ⁵Amsterdam Reproduction and Development, Amsterdam, Netherlands; ⁶Amsterdam Public Health, Amsterdam, Netherlands

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Background: Dried Blood Spot (DBS) sampling offers the convenience of at-home blood sampling, making it an advantageous solution for patients requiring regular check-ups of their hormone levels, such as testosterone. It eliminates the need for venipunctures, which require additional or longer hospital visits, resulting in significant advantages for patients, physicians, laboratory staff and hospitals. DBS samples can be sent by regular mail to the laboratory for analysis, ensuring that results are available during outpatient clinic visits. The aim of this study is to evaluate the feasibility and reliability of using DBS samples for monitoring testosterone levels in patients receiving testosterone replacement therapy (trt).

Methods: A total of 59 males from the andrology outpatient clinic receiving trt (via deeply intramuscular injection of testosteroneundecanoate or dermal application of testosterone gel) were included in this study. Blood was collected parallel by venipuncture (reference value) and finger prick (DBS sample) performed by the patient self after reading the instruction material to guide them and additional instruction from the andrology consultant. Testosterone concentrations in both serum and DBS were quantified using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Pearson correlation coefficient was calculated.

Results: 39 DBS samples were suitable for analysis, while the remaining 20 samples were unreliable due to contamination from testosterone gel (12), improper sampling technique such as finger stamping, blood stacking, or collection of too small droplets (6) or analytical difficulties (large duplicate variation) (2). The correlation coefficient between testosterone concentrations in self-sampled DBS and serum was r = 0.87.

Conclusions: For patients receiving trt via deeply intramuscular testosteroneundecanoate injection, monitoring testosterone levels via DBS sampling at home is feasible, enhancing patient comfort and convenience. Patient education is needed to ensure proper collection of DBS samples, leading to high quality DBS and accurate testosterone quantification.