Blood Volume Status in Patients with Chronic Fatigue Syndrome: Relation to Complaints

Four studies have compared a possible decrease in circulating blood volume in Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients when compared to a healthy population. A more recent study has proven a correlation between RBC volume and OI in chronic OI patients without being diagnosed ME/CFS. The aim of the present study was to relate measured blood, RBC and plasma volumes (absolute and percent normalized) with the orthostatic intolerance complaints in ME/CFS patients. In the included 11 female ME/CFS patients, percentage decrease in normalized blood, RBC and plasma volume was similar for all three components: 83% ± 12%, 83% ± 12% and 83% ± 11%, respectively. In patients with a clinical suspicion of OI (n = 7) all 3 volume components were significantly lower compared to patients without clinical suspicion of OI (n = 4). The difference percentage to normalized Blood volume was 77(7) vs 94(10) (p-value < 0.02), difference percentage to normalized RBC volume was 76(7) vs 96(10) (p-value < 0.01) and difference percentage to normalized plasma volume was 77(7) vs 93(10) (p-value < 0.05) in OI present versus absent. Plasma volumes were plotted against RBC volumes: the relation found was RBC volume = 0.99* Plasma volume + 1.55; p < 0.001; r = 0.90. In line with literature data, this pilot study shows that total blood volume and its components: RBC and plasma volume may be reduced in ME/CFS patients, especially in the presence of a clinical suspicion of OI.