Blood volume status in CFS/ME correlates with the presence or absence of orthostatic symptoms, by C (Linda) Van Campen, Peter C Rowe and Frans C Visser in Front. Pediatr. Oct 2018
Conflicting data have been published on the reduction of circulating blood volume in adults with Myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS). The aim of the present study was to compare blood volumes based on the presence or absence of orthostatic symptoms.
Methods and results:
12 consecutive adults with ME/CFS participated in the study. All underwent dual isotope blood volume measurement and were evaluated for a clinical suspicion of orthostatic intolerance (OI). The mean age was 34 (10) years, and median duration of disease was 7.5 (6-10) years. The mean (SD) absolute blood volume was 59 (8) ml/kg, a value -11 (7) ml/kg below the reference blood volume.
Of the 12 patients, 4 had no OI and 8 had a clinical suspicion of OI. In 8 patients with OI, absolute blood volumes were significantly lower than for the 4 without OI (56  vs 66 ; p<0.05) as were the differences between the measured and the reference blood volume (-14 ; vs -4 ; p<0.02).
Adults with ME/CFS had a significantly lower blood volume if they had a clinical suspicion of OI compared to those without a clinical suspicion of OI, as well as a significantly lower blood volume compared to the expected value. The data suggest that accounting for symptoms of OI could enhance the detection of the subset with reduced blood volume.