Low-grade fever

A low-grade fever (LGF) is when a person's body temperature is slightly higher than normal range but not high enough to qualify as a fever. A low-grade fever is often classified as an oral temperature that is defined as a body temperature between 99.5°F (37.5°C) and 100.9°F (38.3°C).

Prevalence

• In a 2001 Belgian study, 45.7% of patients meeting the Fukuda criteria and 56.5% of patients meeting the Holmes criteria, in a cohort of 2073 CFS patients, reported low-grade fever.

Symptom recognition

• In the Holmes criteria, a mild fever (oral temperature between 37.5°C or 99.5°F and 38.6°C or 101.5°F, if measured by the patient) is an optional criteria for diagnosis, under the section Minor Symptom Criteria. It also appears as an optional criteria for diagnosis under the section Minor Physical Criteria as a low-grade fever (oral temperature between 37.6°C or 99.7°F and 38.6°C or 101.5°F, or rectal temperature between 37.8°C or 100°F and 38.8°C or 102°F) that has been documented by a physician on at least two occasions, at least one month apart.

• Recurrent feelings of feverishness are regarded as a neuroendocrine symptom of ME/CFS in the Canadian Consensus Criteria.