+1 on making lab panels available in diagReport.
Providers often thing in terms of the panels of tests they are sending ... They ask themselves "Is the CBC normal?" a lot.
You can piece some of this together with timestamps, but my experience is that not all parts of a panel (like a CBC) result together.
The Rory Stauton case (https://www.nytimes.com/2012/07/12/nyregion/in-rory-stauntons-fight-for-his-life-signs-that-went-unheeded.html
) highlights how parts of a panel can result at different times and how providers tend to think of panels. If you don't remember, Rory was a young boy who was discharged from a ER in New York while a band count from a CBC was still pending. His bands were extremely high and he later died of overwhelming sepsis. Like all safety events, there was not one thing that went wrong but a series of things ... but not having access what belongs in a panel (ie bands that are still pending) doesn't help.
You could check ProcedureRequest and see if a manual diff is still pending in his case, but if you grouped results together and displayed as one, finalized panel, you run the risk of having a UI that potentially leads a provider to a bad action (ie discharge with incomplete results).
Whether having this functionality is specifically stated in USCDI or ARCH or Argonaut Data Query Guide is somewhat besides the point to me ... I think we all got into this FHIR thing to make things better, not potentially make work arounds that could hurt people. For what it is worth, Epic supports this in diagReport, I am guessing because of the above safety issue. I personally think lab viewers would be great, low hanging fruit to innovate within FHIR (and I've seen people make them with work arounds). However, having seen near misses of incomplete panel results (bands, potassiums, platelets, etc) in clinical practice leads me to not build a lab viewer until panels are in diagReport.
We all got into this FHIR thing to make things better, and we can, just need the right tools.