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NIH/IOM 2015 Definition (SEID)

The recently proposed NIH/IOM 2015 Definition1 (SEID) diagnostic criteria developed by the US Institute of Medicine (IOM) redefines CFS for clinical application.

The IOM was chartered to examine the evidence base for ME/CFS by a number of US federal government agencies – the Department of Health and Human Services (HHS), the National Institutes of Health, the Agency for Healthcare Research and Quality, the Centers for Disease Control and Prevention, the Food and Drug Administration, and the Social Security Administration.

Also on Shoutout About ME:


IOM Committee

Ellen Wright Clayton (Chair), Center for Biomedical Ethics and Society, Vanderbilt University Medical Center, Nashville, TN; Margarita Alegría, Harvard Medical School, Boston, MA; Lucinda Bateman, Fatigue Consultation Clinic, Salt Lake City, UT; Lily Chu, International Association for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis, Chicago, IL; Stanford University ME/CFS Initiative, Stanford, CA; Charles S. Cleeland, University of Texas MD Anderson Cancer Center, Houston; Ronald Davis, Stanford University School of Medicine, Stanford, CA; Betty Diamond, The Feinstein Institute for Medical Research, Manhasset, NY; Theodore Ganiats, University of Miami, Miami, FL; Betsy Keller, Ithaca College, Ithaca, NY; Nancy Klimas, Nova Southeastern University, Miami, FL; A. Martin Lerner, Oakland University, William Beaumont School of Medicine, Rochester, MI, Cynthia Mulrow, University of Texas Health Science Center, San Antonio; Benjamin Natelson, Mount Sinai Beth Israel, New York, NY; Peter Rowe, Johns Hopkins University, Baltimore, MD; Michael Shelanski, Columbia University, New York, NY

About that name – SEID

The IOM recommended that the name of the disease be changed from ME/CFS to Systemic Exertion Intolerance Disease (SEID).

Dr Lucinda Bateman, IOM Committee on redefining ME/CFS (Ravell Call, Deseret News)
Dr Lucinda Bateman, IOM Committee (Ravell Call, Deseret News)

The IOM concluded that the term myalgic encephalomyelitis was inappropriate because there was a lack of evidence for encephalomyelitis (brain inflammation) in ME/CFS patients, and myalgia (muscle pain) was not a core symptom of the disease (this point is heavily disputed by researchers and patient groups).

SEID was not intended to replace usage of ME2.

According to the IOM, “This name captures a central characteristic of the disease: the fact that exertion of any sort—physical, cognitive, or emotional—can adversely affect patients in many organ systems and in many aspects of their lives. The committee believes systemic exertion intolerance disease appropriately captures the complexity and severity of the illness.”

A poll of 1,147 people3 found that approximately 62 percent of respondents rated the name SEID as “pretty bad” or “very bad.” In addition, the majority of respondents expressed negative opinions about the naming process and governmental use of the proposed name.

With such disapproval among patient groups, it is less likely that this new name will gain the types of support required to actualize the adoption of the SEID term4.

Further Cracks in the SEID Definition

The new criteria were not evaluated with data sets of patients and controls4. Findings suggest that the new criteria select more patients who have less impairment and fewer symptoms than several other criteria4.

SEID may also categorize many individuals with major depressive disorder, as well as other medical illnesses5.

As a result of omitting these exclusions, SEID increased the prevalence rate for the illness of 0.42 percent as defined by Fukuda, by 2.8 times5.

In the video below Dr Lucinda Bateman (on the IOM committee) discusses the SEID diagnostic criteria and new name for ME/CFS at an OFFER Education Meeting held on March 4, 2015.



For a full list of the NIH/IOM 2015 Definition (SEID) criteria for ME/CFS, toggle the panel below.

NIH/IOM 2015 Definition (SEID) criteria for ME/CFS

Diagnosis requires that the patient have the following three symptoms:

  1. A substantial reduction or impairment in the ability to engage in preillness levels of occupational, educational, social, or personal activities, that persists for more than 6 months and is accompanied by fatigue, which is often profound, is of new or definite onset (not lifelong), is not the result of ongoing excessive exertion, and is not substantially alleviated by rest, and
  2. Post-exertional malaise,* and
  3. Unrefreshing sleep*

At least one of the two following manifestations is also required:

  1. Cognitive impairment* or
  2. Orthostatic intolerance

* Frequency and severity of symptoms should be assessed. The diagnosis of ME/CFS should be questioned if patients do not have these symptoms at least half of the time with moderate, substantial, or severe intensity.


PHOTO: The Mask Collaboration: Out-takes and BTS by Adam Purcell


  1. Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome; Board on the Health of Select Populations; Institute of Medicine. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington (DC): National Academies Press (US); 2015 Feb. [Abstract], [Full Report]
  2. Bateman, L. The Name And The Report. ME Global Chronicle, 2015. [Full Text]
  3. Petrison, L. Survey Results (Pt. 1): Evaluating a Proposed Name to Replace “ME/CFS”. Paradigm Change, 2015. [Full Text]
  4. Jason, L. Sunnquist, M. Brown, A. McManimen, S. Furst, J. Reflections on the IOM’s systemic exertion intolerance disease. Pol Arch Med Wewn 2015 pii: AOP_15_067 [Abstract], [Full Text]
  5. Jason, L.A.; Sunnquist, M.; Kot, B.; Brown, A. Unintended Consequences of not Specifying Exclusionary Illnesses for Systemic Exertion Intolerance Disease. Diagnostics 2015, 5, 272-286. [Abstract], [Full Text]

Written by Russell Logan

Russell Logan worked as a magazine publisher and editor until forced into early retirement through ill health with ME. He has battled with moderate to severe ME for 25 years. He now lives in Noosaville, Australia.

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