Every patient gets vital signs. They’re … vital, after all. And the presence or absence of fever is one of those vital signs – and may substantially alter the diagnostic approach to a number of patients.
However, I’m guessing few of us universally use central sources of temperature measurement – bladder, rectal, pulmonary artery, or esophageal. We, instead, rely on peripheral measurements – axillary, temporal artery, tympanic membrane, or oral. And, these authors are here to tell us – within the bounds of their low-quality studies – we are being randomly misled.
This is a meta-analysis and systematic review of 75 studies comparing various peripheral temperature measurement techniques to central gold standard. These authors rate ±0.5°C as a reasonable, clinically acceptable limit of agreement – and, frankly, even that seems like enough deviation to be relevant.
In their pooled analysis, however, peripheral thermometers were nowhere close – and the ranges worsened both with fever and hypothermia. In adults, for fever the 95% limit of agreement ranged from -1.44°C to +1.46°C, and for hypothermia the range was -2.07°C to +1.90°C. This led to a pooled sensitivity and specificity for fever of 64% and 96%.
The authors acknowledge multiple limitations to their data, mostly related to biases in sampling and measurement. However, this probably still the best evidence available – and it seems it’s just about a flip of a coin whether a peripheral temperature measurement will miss a true fever.
“Accuracy of Peripheral Thermometers for Estimating Temperature”
http://www.ncbi.nlm.nih.gov/pubmed/26571241
Rude, they didn't include my amazing, seminal article!
Emergency department rectal temperatures in over 10 years: A retrospective observational study.
I use rectal temperatures whenever I suspect a fever.
… even on a 30 year-old? 😉
Rectal does give the most accurate reading, everyone prefers the quick, more pleasant ways, however are we trading accuracy (which is important usually) for comfort and modesty? Ever since the late 70's,- 80's there has been a desperation to replace the rectal temp, and the digital world opened up and on to Ear thermometers and the scan (Star Trek) forehead scanning type.
Seems we may be coming FULL circle, and finding the new, modern, gadgets, aren't replacing the often necessity of obtaining an accurate temperature reading which-The Rectal-Thermometer offered!
This article is a really thorough, professional meta-analysis, but despite the enormous amount of work it represents, the "outcome" here is central temp, instead of a clinically important condition. A super-high temp on a crappy thermometer is still clinically meaningful. This article could be said to be on the "technical efficacy" end of the diagnostic testing hierarchy http://1.usa.gov/1NZYnaY