I may be missing the mark, as I come orginally from a process control background, so apologies if this sounds like an engineering solution. There is a mechanism in OPC (common protocol for getting information out of machines) to where each data point can be identified according to the quality of the data - e.g. OPC_QUALITY_GOOD, OPC_QUALITY_BAD, OPC_QUALITY_UNCERTAIN. There is a further qualification for why the data is bad (connection problems, config error, etc) but the record still contains a actual value, so it can still be plotted, but if it can also be filtered out. I guess this is essentially what you were saying Vince.
Unless I've misunderstood what Sam has proposed, the problem with a substituted value is that it's not going to reflect the recorded value - ie. a chart won't show the "true" erroneous data. -Tom ________________________________ From: Vincent McCauley [mailto:vin...@mccauleysoftware.com] Sent: Wednesday, 1 March 2006 2:12 PM To: openehr-technical at openehr.org Cc: Tom Beale; Heath Frankel Subject: Re: Pathology numeric values not supported in DV_Quantity Hi Sam, This case is I believe actually a measure of accuracy of a result. In my pathology system, I deal with it by having a separate attribute on quantity It takes values such as >, <, >=, <=, ~ (~ => approximately, I => Inaccurate) the value "I" may be used for instance when an analyser returns a potassium value which on subsequent examination of the blood is shown to be erroneously high due to haemolysis. This is usually accompanied by some text which is displayed instead of the numeric value e.g. HAEM but the underlying numeric value needs to be stored anyway as well. This of course makes the logic for deciding whether a result is within a normal range more interesting and graphing routines etc need to take this flag into account. I don't feel strongly whether you deal with this as part of the quantity datatype or have a new datatype inheriting from quantity. Regards Vince Dr Vincent McCauley MB BS, Ph.D McCauley Software Pty Ltd ----- Original Message ----- From: Sam Heard <mailto:sam.heard at oceaninformatics.biz> To: Heath Frankel <mailto:heath.frankel at frankelinformatics.com> Cc: Tom Beale <mailto:thomas.beale at oceaninformatics.com> ; Openehr-Technical <mailto:openehr-technical at openehr.org> Sent: Wednesday, March 01, 2006 12:41 PM Subject: Re: Pathology numeric values not supported in DV_Quantity Hi everyone, We want to report an issue that has arisen in data processing in Australia. The issue is the somewhat random ability of systems to report a >xx or <yy range where a quantity is expected - there are still units and still a normal range. This is common with TSH and GFR - but can turn up in unexpected instances - e.g. we had a baby with a HCO3 of <5 mmol/L. This can be dealt with at present by substituting an interval - but it is a bit wierd as there is still a normal range - it kind of works as there is only a lower or upper value of the interval and so this single quantity can carry the normal range. The point is that it is really a point measurement that is outside the range of the measuring device. Also, it means that we will have to have archetypes that allow multiple datatypes for all quantities that could conceivably be measured in this way. The alternative is to consider a DV_QUANTITY_RANGE that inherits from DV_QUANTITY - it still has only one value - but now it has the ability to set this as the upper or lower value - and also whether this number is included or not. The advantage is that there would still be a number to graph and this data type could always be substituted for a DV_QUANTITY (ie without archetyping). I wonder what others think. Cheers, Sam -- Dr. Sam Heard MBBS, FRACGP, MRCGP, DRCOG, FACHI CEO and Clinical Director Ocean Informatics Pty. Ltd. <http://www.oceaninformatics.biz/> Adjunct Professor, Health Informatics, Central Queensland University Senior Visiting Research Fellow, CHIME, University College London Chair, Standards Australia, EHR Working Group (IT14-9-2) Ph: +61 (0)4 1783 8808 Fx: +61 (0)8 8948 0215
