Calculating Time between time stamps

[davordzi1951]

We're developing Qlik Sense apps for a hospital and we need help on how to calculate the time difference between STARTTIME and SPECIMENCOLLECTIONTIME  formatted to "hh:mm:ss"? Also how can the results be ranked in a Qlik Sense visualization object? Which visualization chart is appropriate for this?

Here is a snapshot of the table we're using.

[Gysbert_Wassenaar]

Basically this: Interval(SPECIMENCOLLECTIONTIME-STARTTIME, 'hh:mm:ss')

But your fields need to be datetime (aka timestamp) values. String values are text and can't be subtracted. 

How you visualize those values depends on the purpose. What is the question that you want to answer with the visualization? Perhaps you should just start with a bar chart sorted in descending order by the interval values.