Methods for measuring plasma volume (PV) have rarely been validated or compared, and some are unsafe in certain populations (e.g., pregnancy). We aimed to develop and evaluate a PV method using hydroxyethyl starch (HES) that is safe in women of reproductive age and could be used in pregnancy. A convenience sample of healthy nonpregnant women (n=12) of reproductive age participated in a comparison study using two indicator dilution methods − HES and indocyanine green (ICG), and three estimations − Kaplan, Hurley, and Nadler equations. Baseline blood samples were collected; we injected ICG and HES separately, each followed by post-injection sampling. We compared HES PV to the other methods using Bland-Altman analysis. Participants had mean±SD age of 25.8±7.5 years and mean BMI of 21.7±1.7 kg/m2. Mean PV estimations for HES, ICG, Kaplan, Hurley, and Nadler methods were 2,046±392 mL, 2,765±820 mL, 2,443±464 mL, 2,407±301mL, and 2,373±406 mL, respectively. In each analysis, differences for 11/12 participants were within the Bland-Altman limits of agreement, ±2 SD from each mean difference. In conclusion, PV measured by HES was >300 mL lower than other estimates, but had a narrow distribution within the expected range. Future studies should validate methods for PV measurement across populations, including pregnancy.

The authors have declared no competing interest.

This study was funded by a grant from Bill & Melinda Gates Foundation (PI: ERS; Investment # INV-016930).

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The Institutional Review Board of the Office for Research Protections at The Pennsylvania State University gave ethical approval for this work.

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