Fast Five Quiz: How Much Do You Know About Chronic Fatigue Syndrome?

Michael Stuart Bronze, MD


December 04, 2015

The most consistent laboratory abnormality in patients with CFS is an extremely low ESR, typically in the range of 0-3 mm/h. A normal ESR or one that is in the upper reference range suggests another diagnosis. Most patients with CFS usually have two or three of the following nonspecific abnormalities:

  • Elevated IgM/ IgG coxsackievirus B titer

  • Elevated IgM/IgG human herpesvirus 6 titer

  • Elevated IgM/IgG C pneumoniae titer

  • Decrease in natural killer cells (either percentage or activity)

The white blood cell count in patients with CFS is normal. Leukopenia, leukocytosis, or an abnormal cell differential count indicates a diagnosis other than CFS, and another cause should be pursued to explain these findings.

Results of liver function tests are within the reference range in patients with CFS. Increased levels of serum aminotransferases, alkaline phosphatase, or lactic dehydrogenase should prompt a search for another explanation because these values are typically normal in CFS. Serum protein electrophoresis is normal in patients with CFS but may be used to rule out other diseases that cause fatigue, including lymphoma and myeloma. Urinalysis findings are unremarkable in CFS.

For more on the workup of CFS, read here.