2021 · Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · paywalled
Sex Hormone Therapy and Tenofovir Diphosphate Concentration in Dried Blood Spots: Primary Results of the Interactions Between Antiretrovirals And Transgender Hormones Study
Grant et al.
The finding, in our words
Dried blood spot concentrations of tenofovir diphosphate were comparable in transgender women, transgender men and cisgender men after four weeks of directly observed pre-exposure prophylaxis, although transgender men showed lower levels than cisgender women. Serum sex hormone concentrations were unaffected by antiretroviral therapy, and all participants achieved drug levels associated with high HIV protection, demonstrating the feasibility of therapeutic drug monitoring via microsampling in this population.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
Home DBS sampling gave testosterone results that agreed well with venous blood in men on intramuscular testosterone undecanoate, but showed falsely high values in those using topical gel, likely from skin contamination. Patients preferred home collection for its convenience, suggesting DBS is viable for decentralised monitoring of injectable testosterone if patients are taught proper technique.
Olthof et al., Clinical chemistry and laboratory medicine (paywalled) · source ↗
A 2025 review maps 28 microsampling devices, from dried spots and volumetric absorptive tips to upper-arm liquid capillary collectors, and names what a laboratory must control before their results are used: the haematocrit effect in non-volumetric dried samples, interstitial fluid from finger milking, volume, haemolysis and transport stability. Regulators on both sides of the Atlantic ask for the same two things, a device the patient can use safely and a sample fit for the test.
Subcutaneous testosterone undecanoate injection was equally acceptable to intramuscular injection despite causing more pain at 24 hours, with most men preferring the intramuscular route. Pharmacokinetic analysis using dried blood spots showed a later peak concentration after subcutaneous injection, but no clinically meaningful differences in overall exposure, suggesting subcutaneous administration is a viable alternative without dose adjustment.
Turner et al., Journal of the Endocrine Society (paywalled) · source ↗
Finger‑prick dried blood spots gave almost identical nandrolone and testosterone concentrations to venous samples. Home self‑collection for 21 days was well tolerated, showing that microsampling supports decentralised therapeutic drug monitoring without clinic visits, venesection or frozen storage.
Singh et al., The Journal of clinical endocrinology and metabolism (paywalled) · source ↗
In AML and CLL, 91% of VAMS venetoclax results fell within 20% of plasma after individualised haematocrit correction; in home sampling, 18 of 21 patients self-sampled independently and 76% of returned samples were analysable, which shows home microsampling is workable, though the authors ask for multicentre validation.
Levens et al., Clinical Pharmacokinetics (paywalled) · source ↗