Yes, a plasma glucose value (also called "blood sugar level" or "blood glucose" or BG) of 84 would be considered normal. Anything below 100 is okay. Depending on how recently you ate and how much you ate, a level of up to 200 may be okay.
These numbers are when the lab reports the measurements in milligrams per deciliter (mg/dl), which is used in the United States. There's another system of reporting BG in most of the world, that would have different numbers. This other system reports BG in millimoles/liter (mmol/l), and is 18 times smaller than mg/dl. So, a BG of 84 mg/dl would be the same as 4.7 mmol/l, the normal level should be below 5.6 mmol/l, and the highest value soon after a big meal should be below 11.1 mmol/l.
Diabetes is diagnosed when fasting BGs are 126 mg/dl (7 meq/l) or higher, or when random BGs are over 200 mg/dl (11.1 mmol/l). As you can see, there's an area between normal and diabetes; this zone is called by various names, such as "impaired fasting glucose" (IFG) and "impaired glucose tolerance" (IGT). People with impaired glucose tolerance or impaired fasting glucose have a significant risk of developing diabetes and thus are an important target group for efforts to prevent the development of diabetes.Hope this helps!
If I understand your question - you're concerned about it but do not have diabetes.
Blood sugar USED TO BE 140 to qualify as a diabetic.
It was recently reduced to 120 - HENCE THE SUDDEN SURGE IN DIABETIC DIAGNOSES.