Determining a Fever Threshold
Determining a Fever Threshold for Temporal Artery Thermometry
Threshold Defining Fever
•A threshold for defining fever is the temperature level above which false positives due to normal variations in temperature, including range of normal mean + circadian effects + other effects (metabolic, ovulation, etc.) are unlikely.
Threshold for Fever Workup
•Not all fevers require a fever workup. A fever workup is an early management tool in assessment of the likelihood of septicemia or bacteremia, and initiated whenever an infectious source is suspected. The level of temperature triggering such that investigatory workup is sufficiently high to avoid false positives resulting inunnecessary discomfort and expense for the patient, but low enough for early identification and intervention.
Primary Points
•Temperatures measured with temporal artery thermometry may be higher than normally seen with other clinical methods, and therefore require an adjustment in both protocol and perception.
•No one value can apply to every temperature measurement site. Note old rule of thumb: Rectal temperature is ~1°F higher than oral temperature and ~2°F higher than axillary temperature.
•Recommended threshold for fever workup using arterial temperature assessment is a single temperature >101.8°F, or a temperature >101.2°F sustained for more than 1 hour.
•Adjustment of ~1°F is necessary to raise the temperature level normally mandated for fever workups to prevent false positives, unnecessary cultures and blood tests, etc.
Physician Recommended Guidelines for Fever Workup1
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| Core & |
| Oral & Temporal |
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Temperature Site |
| Artery in Oral |
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Temporal Artery |
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| Calibration |
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| Single value |
| Single value >101 |
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Fever Workup | >101.8 |
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| Sustained values |
| Single value >99 | ||
Recommendation | Sustained values |
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| (>1h) >100.4 |
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| (>1h) >101.2 |
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| 1Source on file at Exergen Corporation |
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