Re: [Gnumed-devel] Measurements (was: New developer searching for a task)

[Dr Elizabeth Dodd]

Quoting Christof Meigen <address@hidden>: 
 
 
> - My general intention would be to leave the decision 
what 
> value is 
>   normal and what not to the doctor, based on the 
avaliable 
> information 
>   on the patient (age, diagnosis, smoker etc) and 
published 
> norms. 
>   I see that this is strongly against the intention of 
Labs, 
> who 
>   probably claim to be the only ones who know how to 
judge the 
> things 
>   they measured (and don't publish how they come to that 
> judgement). 
>    
> - Imagine a doctor changes Labs, and a value of a 
patient is 
> marked 
>   abnormal, when the very same value two weeks ago was 
> judged 
>   'normal'. This _might_ be because the first lab 
measured 
> with a  
>   different method (which for example has a larger 
error, so 
> the 
>   slightly abnormal measurement was still marked normal) 
but 
>   it also might be because the first Lab just used a 
> different 
>   norm. 
 
Just to totally confuse matters, by statistical definition 
we are leaving out the 'normal' people who are are 2 
standard deviations from the mean. Therefore 2.5% of 
normal persons have 'hi' results and 2.5% of normal 
persons have low results on a given test. That is the 
result of the way the 'norms' are calculated.  
Then add the confusion by labs with different refernece 
ranges as just described. The doctor seeing the patient 
has to make a decision about the result in the context of 
the patient, (we treat patients not lab results) and must 
be able to mark the result as satisfactory or 
unsatisfactory regardless of lab norms. 
(if this doesn't translate well in German, I can try 
simpler English next time) 
Liz