You can get your ESR measured, and tell your lab or doctor to give you a copy of the results. Low ESR results are NOT flagged by commercial labs, so you have to look at the paper with your own eyes. Less than 3 is not good (see below).
The most consistent laboratory abnormality in patients with CFS is an extremely low erythrocyte sedimentation rate (ESR), which approaches zero. Typically, patients with CFS have an ESR of 0 to 3 mm/h. A normal ESR or one that is in the upper reference range suggests another diagnosis. https://www.consultant360.com/content/chronic-fatigue-syndrome-update-diagnosis-primary-care