Analysis of women's health-related proteins in dried blood spots

Female fertility is tightly regulated by hormones circulating in the blood. Currently, the primary blood sampling procedure for such analysis is a venous puncture, necessitating the involvement of health care professionals. A minimally invasive alternative to obtain and measure blood protein levels can be offered by self-sampling devices that generate quantitative dried blood spots (qDBS). The aim was to assess the potential and accuracy of determining fertility-related blood biomarkers in quantitative DBS (qDBS, Capitainer AB) using multiplex immunoassays. Nine proteins were evaluated for their detectability and precision in quantifying protein levels in qDBS. In a pilot study with samples from anonymous donors, all proteins were detectable above the background, but only five of the nine proteins could be quantified accurately in qDBS. The measured protein concentrations in qDBS were close to levels previously reported in the literature for serum and plasma levels, supporting the potential of the results. A second pilot with 100 qDBS samples confirmed the utility of the five quantifiable proteins. The results showed differences between males and females and three proteins associated with age ranges related to the onset of menopause. With a third study of 100 qDBS and plasma samples, we replicate our observations and compare the qDBS data with plasma levels obtained in a clinical chemistry lab. The levels correlate well, across the techniques and sample types, for three of the hormones (Pearson R² 0.84-0.94). So far, our results have shown noticeable and reliable differences in protein levels between the donors, sexes, and ages. Their utility to support clinical diagnostics is being tested.