Answer: Great question. As you have done in your case, it is essential that every diabetic patient with an altered GCS should have blood glucose values determined.
You are correct that not every patient must have a blood glucose determination with a GCS of 15. Our concern however is the patient who was initially found to be hypoglycemic, then receives a therapy from EMS, then possibly refuses transport to the hospital.
It is possible for a patient to have a GCS of 15 yet have glucose levels which fall outside of “normal” parameters. Providing accurate counseling to the risks and benefits of transport would be more accurate if a repeat blood glucose determination was performed: if they were still “low”, their risk of recurrent hypoglycemia is much higher.
As such, the SWORBHP Medical Council suggests that any refusal of transport must have a repeat glucose performed if therapy to reverse hypoglycemia was provided. In general, we also recommend a repeat glucose on most patients in this situation. However if your patient has a full return to GCS 15 AND is being transported, then it would be acceptable to not repeat the glucose.