Mixed absolute value and delta Events in a History

@siljelb posted an interesting clinical modelling requirement that concerns the use of differential value Events, i.e. ‘deltas’.

It made me wonder if we should consider how a mixture of absolute value and delta Events would work. Right now it is perfectly legal, but I doubt if anyone’s software would handle it intelligently because it would not be expected. But that could be easily fixed, and I don’t see anything wrong with such a mixture - indeed, recording an absolute value every so often among delta-value recording is a typical thing to do in certain engineering systems.

Here’s the relevant RM spec for reference.


I’m not so sure that this clinical scenario should be modelled using a single archetype because of the associated RM and implementation gymnastics required, but mostly because I’m of the opinion they are two separate concepts that need two separate archetypes.

My thoughts inline in the original thread - Change over time in an OBSERVATION measurement, represented as % - #8 by heather.leslie

Maybe there are other clinical scenarios that warrant this discussion, but I can’t think of any at the moment. Happy for other scenarios to be suggested…

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For Oncology data ,we are looking for mapping tumour / disease response after chemotherapy / radiotherapy . Currently could not find any particular archetype to capture this data. But this can be exmaple to capture delta and original values differently as we will capture it over months / year.

Hi Anjali,

Good potential use case. Can you be more specific about your requirements? For example, do you record the actual delta during set interval of time?



We are trying to capture pretreatment tumour , nodes size . Then after 6 cycles of chemotherapy which can be 4-6 months time from the initial record . During followup period , radilogical evaluation will be done evry 3-6 months interval and the response will be captured. If the tumour recur after 2 years at same site then we will have again series of mesaurements to capture.
We are planning to build a longitudinal record for cancer patient hence this becomes very important. Every event, actual tumour size will be recorded and even delta to extrapolate of its > or < 50% reduction or increase in size to mark it partial / complete response .

Hope this helps.

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