iSTAT users

You can run controls as unscheduled but it will not give you credit for doing the scheduled QC.  Your iSTATs will lock out testing even if that QC was acceptable when run as unscheduled.  I don't think the iSTAT will allow you to run the QC before your scheduled time. You can turn off your schedule QC , run the QC then reset your schedule again for your next run. 

No, it won't give you credit for running the QC before the scheduled time.  You can run it but if it's before it's due it will require it when the scheduled due date comes around.  It gives you a grace period after the date but nothing before.