For how long does body temp need to be elevated to be considered a fever? what's the lowest temp considered to be a fever?

Feeling a fever?: Most patients can report a subjective 'feeling' of a fever - and I like to go on that. If you're being technical, I count 100.5 as my 'cut off' although some docs will allow lower values when looking at a population. Not sure if you're familiar with a 'normal distribution' or Gaussian curve but 'somewhere' you have to make the cut off. If you felt it, then I count that as real-even a short time OK

Oral, rectal or axil: 38 C or 100.4 F is usually the cutoff for "fever" Oral is the most common, but rectal temps are the most accurate. Just one measurement of 38 or higher, or 100.4 or higher is considered a fever.