Retrieving Results Individually
Applications developers use the MED to determine which data are relevant to their needs. In this example, a developer of a clinical application might wish to produce a report of all the potassium (K) tests. The lab might have more than one such test (K#1 and K#2) and the application developer has to know this in order to retrieve all the data. If the lab adds a third test (K#3) to the MED, the application developer can only retrieve new data if he knows about the addition (broken lines). If he doesn't, his program won't work. But the developer may not have any way of knowing the lab has changed its vocabulary and the lab may not know which developers to notify about their changes.