2025 · The journal of applied laboratory medicine · paywalled
Systematic Reduction in Estradiol and Testosterone Measurements due to Serum Separator Gel in Blood Collection Tubes: Implications for At-Home Fertility Testing
Vasavan et al.
The finding, in our words
Capillary tubes with serum separator gel gave 13% lower estradiol and 8% lower testosterone than non-gel capillary tubes, with discrepancies up to 19% and 14% versus venous tubes; other fertility hormones were unaffected. Conversion formulas were derived, but the study did not evaluate home collection workflows.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
Capillary fingerstick sampling showed high correlation and agreement with venous sampling for serum AMH but with proportional bias, so it may improve access to testing yet should not be considered fully interchangeable without further validation.
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.
Earlobe capillary microsampling of 100-250 µL found good agreement with venous draws for progesterone, concordance 0.911, and 17β-estradiol, concordance 0.919, across menstrual cycles, showing suitability for decentralised monitoring. However, participant-reported burden was not assessed, and further validation is required in elite athletes.
In 46 women under hormone monitoring at Columbia University Fertility Center, oestradiol, LH, FSH, progesterone and hCG measured on routine immunoassays from 400 to 600 microlitres of upper-arm capillary blood collected with TAP Micro Select agreed closely with paired venous results for every analyte, with correlation and concordance high throughout. It is the evidence that puts a self-collected sample inside the daily monitoring of an IVF cycle.
The study found excellent agreement between hCG levels measured in remotely collected capillary blood and standard venous samples, with a near-perfect correlation. This demonstrates that remote self-collection is a feasible and acceptable alternative for serial pregnancy monitoring, reducing the need for clinic visits.