Dried blood spot (DBS) sampling has some major advantages over venous sampling.  It is less invasive and easier to sample, and it is simpler to transport and store due to the reduced sample volume. Efficiency is high because instead of by venous sampling patients can, with the proper training, sample the bloodspots themselves from their own home. If the DBS samples are sent to the laboratory at the right time, the measurements to determine the concentrations have been performed before meeting the doctor. For doctors it is convenient to discuss the test results directly at the outpatient clinic, instead of having to call two weeks after the appointment to discuss the test results which is currently often the standard procedure.

As steroid hormones (like cortisol and testosterone) are preferably measured in the early morning, these hormones are interesting candidates to measure using DBS sampled at home. To be able to facilitate DBS sampling for diagnostic purposes, the optimal conditions for storage and shipping of DBS need to be determined in order to guarantee the stability of the analytes to be measured in DBS. In this research project, blood spots from 40 healthy volunteers (20 males, 20 females) will be collected and stored at the different temperatures a package with DBS can encounter during the postal process (-20°C, 4 °C, room temperature, 37°C). Directly after sampling and after 1 day, 7 days, 14 days, 3 months and 6 months under these temperature exposures, stability of several steroid hormone concentrations will be assessed. A validated DBS LC-MS/MS method for cortisol, cortisone, corticosterone, 11-desoxycortisol, 21-desoxycortisol, 11-desoxycorticosterone, testosterone, androstenedione, and 17-hydroxyprogesterone is available in the Endocrine Laboratory of Amsterdam UMC. The results will show which conditions are acceptable for transport and storage of DBS to be able to measure these steroid hormones. With this information, the DBS sampling can be implemented in diagnostics.