Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -re8edb83fcba5c355198efc30944d51c54814bdbe -r00ff72e0b1cf3002e660d850346e26e1209e2b24
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision e8edb83fcba5c355198efc30944d51c54814bdbe)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 00ff72e0b1cf3002e660d850346e26e1209e2b24)
@@ -1176,6 +1176,12 @@
     {
         DG_RESERVOIR_ID_T activeRes = getDGActiveReservoir();
 
+        if ( TRUE == isBloodLeakZeroingNeeded() )
+        {
+            // If the sensor has drifted request a zero prior to transitioning to treatment
+            zeroBloodLeak();
+        }
+
         patientConnectionConfirm = FALSE;
         doorOpened               = FALSE;
         setStartReservoirVolume( activeRes );