How Do You Diagnose Diabetes With A Diabetes Test?

Diabetes, either type 1 or type 2, is diagnosed with a blood test.

Specifically a fasting blood test to look at the blood glucose levels to see if it is high, low or normal.

As well as blood test results, there may often be symtoms of diabetes that will support the diagnosis of diabetes.

Sometimes diabetes has no symptoms and only shows up on blood tests.

If this is the case, it's still important to treat and monitor the diabetes so that it does not cause long term problems of diabetes.

So here are the blood glucose levels and how they diagnose diabetes or prediabetes.

Fasting Blood Glucose Levels: How To Interpret

The cutoffs used in the US [1], for blood glucose levels in terms of low, normal or high are:

Glucose Level = Normal = 70 to 100 mg/dL (or 3.88 to 5.55 mmol/L)

Glucose Level = Pre-Diabetes = 100 to 125 mg/dL (or 5.55 to 6.94 mmol/L)

Glucose Level = Diabetic = 126 mg/dL (or 7mmol/L) or above

In 1997, the American Diabetes Association lowered the blood glucose level which diagnoses diabetes from 140mg/dl (or 7.8mmol/L) to the 126 mg/dl (or 7mmol/L) that is currently used.

If there are 'typical' symptoms of diabetes present, then sometimes one blood test which reaches high glucose levels (diabetes or pre diabetes) will diagnose diabetes.

But if there are no symptoms, then a repeat blood test may be needed to confirm diabetes.

Note that these are fasting blood glucose levels, which are more reliable than random blood glucose levels to diagnose diabetes.

If you use random blood sugar levels, then the levels of cutoffs to diagnose high, normal or low glucose levels are different.

Source:

[1] The Mayo Clinic, www.mayoclinic.com, 2006

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