A client received 20 units of NPH insulin at 8:00 AM. When should the nurse check for hypoglycemia?

The correct time to check for hypoglycemia after administering 20 units of NPH insulin at 8:00 AM is in the late afternoon, closer to 5:00 PM. NPH insulin is an intermediate-acting insulin that typically begins to take effect about 1 to 3 hours after administration, peaks around 4 to 12 hours, and lasts 12 to 18 hours.

After administering the insulin in the morning, it is crucial to monitor the patient for signs of hypoglycemia during the peak action period, which means around late morning to early afternoon. Checking at 10:00 AM and 11:00 AM would fall too early in the timeline, especially since the peak action might not yet fully manifest.

By 5:00 PM, the nurse would be monitoring the client during the later part of NPH's action window when there is a higher likelihood of hypoglycemia occurring as the insulin starts to wear off and glucose levels may drop. Hence, monitoring at this time is the most appropriate choice to ensure patient safety.