[Gnumed-devel] Measurement conversion concepts

[Busser, Jim]

Am I correct to believe that so far (in gnumed_v19) the only column so far 
committed to assist lab data standardization is

        conversion_unit

in table

        clin.test_type?

Some thoughts about achieving the standardization …

1. Standardization can be important even in cases where we could be talking a 
single test_type e.g. within a single patient

        (a) weight recorded on some occasions in lb and on other occasions in kg
        (b) lab switches methods / assays (and starts reporting a different 
normal range)

2. Standardization obviously becomes important in cases where different 
test_types (with different units) have been aggregated

3. Some unit conversions are constant and re-usable independent of which test 
or substance is being described

        e.g. weight e.g. lb --> kg
        e.g. weight / volume e.g. mg / dL ---> g/L

whereas mg --> mmol would obviously vary with the substance / test and so too 
could units of the substance however even here limited conversion within a 
substance could be reasonable e.g. within a substance

        u / mg x 1000 = u / g

4. Simple initial cases could be  (after deciding the amount of precision)

        --> lb / 2.2 = kg
        ..> in x 2.54 = cm

5. Note to self about my posting from Nov 27 which included

        From Local Laboratory to Standardisation and beyond Applying a common 
grading system
>       http://www.phuse.eu/download.aspx?type=cms&docID=201

-- Jim