Lets say BG is 70-80 prior to eating and lantus is scheduled to be given 3 hours after meal. 50% of meal is taken and hs snack given. No order to recheck BG prior to lantus and no symptoms of hypoglycemia...do you check BG again?
I would probably check the blood sugar again. Just remember that unlike Novolog/Humalog, Lantus doesn't begin working until 4hrs after administration. Seeing how the pt had a bedtime snack, it is doubtful the pt will drop his sugars over night.
Think of Lantus as a time-released medication. Low doses over a longer period of time. I would give the insulin UNLESS the BS is below 70 and patient refuses snack. And I would make sure the snack contains protein to keep BS up longer. No harm in checking BS before bedtime or even in middle of the night, just for documentation sake and to make you and pt feel better.