When modelling certain scores who depend on particular clinical measurements such as lab values, an issue has been identified where the score in question comes in several different versions where the only difference is the units used.
For example, in SOFA score, the element “Respiration” depends on the calculation of a PaO2/FiO2 ratio, which may be given in either mmHg or kPa. This of course means that the threshold values differ between the different units, although they are equivalent when converting between the different units.
An example value from SOFA score:
2: 200 - 299 [PaO2/FiO2 ratio is between 200 mmHg and 299 mmHg.]
2: 26.6 - 39.8 [PaO2/FiO2 ratio is between 26.6 kPa and 39.8 kPa.]
We currently don’t have an established way of modelling this. In the Hscore archetype we’ve suggested doing it by choosing one unit for the value name and explaining the other in the description, like this:
44: 1.5-4.0 mmol/L [The Triglyceride level is 1.5-4.0 mmol/L or 132.7-354 mg/dL.]
However, this makes it difficult or impossible to implement the archetype using the alternative unit.
We’ve thought of the possibility of specialising the archetype for sets of alternative units, based on sets in actual clinical use in different localities.
However, we’d like to seek the opinions of the community on how to do this. Ideally we’d like to be able to specify these sets of alternative units in the same archetype, if possible.