Not everyone who takes part will meet the study criteria and therefore we won’t ask everyone to provide a saliva sample. This is because we are using narrowly focused criteria (IOM/NAM & CCC). We predict around one in four people will not meet these criteria but this does not mean that they do not have ME/CFS – Only that they aren’t eligible for this particular study. This could be for a number of reasons (e.g. how their symptoms present or if other health conditions would make analysis difficult).


Unfortunately, due to the large size of the study and the importance of avoiding any bias, we are unable to inform participants of the reason  they did not meet the criteria. However, the answers you provide at the questionnaire stage are still valuable to ME/CFS research and participants may still be contacted about future research opportunities if you consented to this.


For more information on the criteria used in the study click here.

The largest ever DNA study of ME/CFS

A partnership between

Action for ME logo
Forward ME Logo
UKRI MRC Human Genetics Unit logo
National Institute for health research