I think this all depend on whether the inventory table needs to be permanent or would vary at different points in time.
You could make a reporting table and then use a script to populate that table with data based upon the reporting date. You could then use the reporting table as a dynamic historical record of a sample's history.
Sample Table to Reporting table using id_sample and a global field ReportDate and allow creation of new records.
Set the Report Date to the date for the report then run a looping script like this to create the report records.
SetField(sample_REPORT|reportdate|::Status) to "Null"
If you place the related Status Field on your layout you could now tag all items as to "Discontinued", "Missing" or "Present".
Next time you need to update status you rerun the script with the run date for that date and you'll get new status fields to report on.
“Poets have been mysteriously silent on the subject of cheese.” ― G.K. Chesterton, Alarms and Discursions