Level of fasting blood sugar to diagnose pre-diabetes and diabetes


Q: Dear Doctor, Is a Hgb A1c of 5.9 on 1 occasion, fasting blood glucose of 111 and 99 on 2 separate occasions enough for a diagnosis of diabetes?


A:   Diagnostic criteria for diabetes are the ff:

Symptoms of diabetes (overeating, frequent urination and frequent drinking, weight loss, etc) + random blood sugar =/> 200mg/dL
Fasting blood glucose =/> 126 mg/dL
2-hour plasma glucose =/> 200mg/dL during an oral glucose tolerance test

HgbA1c is not part of the diagnostic criteria but it is being used to monitor diabetes control. A fasting blood glucose value between 100mg/dL to 126 mg/dL would mean an impaired glucose tolerance, which is considered a pre-diabetic state. If it exceeds 126mg/dL, diabetes is diagnosed. Sometimes, through years of clinical experience, doctors don’t strictly follow these criteria in labelling patients as diabetics or pre-diabetics. Pre-diabetics, especially if there is a strong family history will eventually have diabetes, most of the time sooner than later. There could be some other factors or previous labs you’ve had (urine test which showed high glucose, etc) that made your doctor think you have diabetes or most likely to have diabetes. Regardless, you need to drastically change your lifestyle and diet. A moderate regular exercise regimen can never be overemphasized in the management of diabetes. A healthy diabetic diet should also be followed. It's a shame these measures are often ignored by diabetic patients. There are some diabetics controlled on exercise and diet alone and it will always be the first-line treatment since these don’t have unavoidable, undesirable side effects. I do hope I have answered your question and take care always.  

Related Q&A

Q: Ive been so tired for months now! Out of the blie this morning I tested my fasting blood sugar level and it was 164. ...

Q: When my sugar is low I experience exaggerated movements. Why

Q: When my sugar is low I get exaggerated movements. This has happened 3 times now Why?

Q: Think have diabetes..dont have medical insurance nor a primary physician. Found a lab that will test for diabetes sho...

Q: Im worried I have ms my cousin has it and suggested I talk to my doctor I'm having severe symptoms and I need advice ...


Dr. James Obaji M.D.

  • 247 Reviews
  • Family Physician

Dr. Suneel Sharman M.D.

  • 190 Reviews
  • Family Physician

Dr. Pat Golden M.D.

  • 169 Reviews
  • Cardiologist

Dr. Kunaal Jindal M.D.

  • 112 Reviews
  • Plastic Surgeon