From: "Walter Driedger"
References: <3DD2EC20.2FB10158@maine.rr.com> <email@example.com> <3DD4487C.77549C50@maine.rr.com> <3DD65C67.8C2CE98C@maine.rr.com>
Subject: Re: Temperature Measurement Stability - +/-3.5 microdegrees
X-Newsreader: Microsoft Outlook Express 6.00.2720.3000
Date: Sun, 17 Nov 2002 03:40:28 GMT
NNTP-Posting-Date: Sat, 16 Nov 2002 20:40:28 MST
Organization: Shaw Residential Internet
37 C is an average, typical human body temperature. Firstly it is an
average; actual temperatures may vary. Secondly it is typical. Daytime,
nightime, time of the month, oral, rectal, arm pit; change is the only
constant. Finally, it is the human average. As such it does not apply to
dogs, gerbils, parakeets or iguanas.
It is not some universal constant like the speed of light or even the triple
point of water. The is no more point in measuring human body temperature to
an accuracy greater than .1 degree than there is in declaring the
temperature of the weather in a given city, at a given time to be 37.01. It
varies more than 2 degrees from one side of the street to the other.
"Raymond E. Rogers" wrote in message
> Francis wrote:
> > I have to ask, what on earth requires that level of accuracy.
> > I am an engineer, not a scientist.
> > Francis
> I don't know if the question was directed at me but....
> Consider medical testing, the chemical processes are tuned to 37degC.
> In actual measurements the sensitivity of diagnostic reaction rate to
> temperature is 1%/.15degC . We are attempting to bring to in office
> diagnostics a series of general health tests for veterinary clinics at
> the price range of $3.00 per test with an accuracy of around 4%. I am
> trying to move the electronics control system completely out of the way
> of the measurement; believe me there are a lot of other items that
> contribute to the measurement uncertainty. I want to be able to say
> with certainty that the temperature is stable. In fact there is a case
> of cascading specs here: 4:1 for the chemistry and then 5:1 for the
> electronic instruments, but I really think (in this day and age) that
> the electronics should not be the limiting factor.
> In the end I hope to see the technology move from the veterinary office
> to the doctor's office and help bring down the cost of medicine. It
> will probably happen by 2020, the question is who is going to do it.