“What test is most likely to diagnose diabetes?”
I want to test for diabetes. What test is most likely to diagnose diabetes?
5 Answers
The fasting blood glucose test which measures the blood sugar after overnight fasting. Fasting blood sugar level of 99mg/dL or lower is normal. Blood glucose between 100 to 125 mg/dL means that you are pre-diabetic. Blood glucose greater than 126 means that you have diabetes. Thank you.
The diagnosis of diabetes mellitus may be done with a random blood sugar greater of 126 mg/dL and the presence of symptoms as increased urination, thirst, appetite and weight loss; or 2 different samples of hemoglobin glycosylated greater than 6.5%; or after an oral glucose tolerance test greater than 200 mg/dL at 2 hours. As you can see, it's not clear cut with
just one test, it is a combination of symptoms and confirmation with blood work.
just one test, it is a combination of symptoms and confirmation with blood work.
Dr. Jennifer Rittenberry
Endocrinology, Diabetes
Usually diabetes mellitus is diagnosed with a fasting glucose of 126 or higher, or a random sugar of 200 or over with symptoms (increased thirst or increased urination, weight loss) or a Hemoglobin A1C value of 6.5 or higher.
A urine test or a fasting blood sugar level. Your doctor can administer either one of these tests for you.
RB Thomas, MD
RB Thomas, MD
This the update literature“ DIAGNOSTIC CRITERIA
Fasting plasma glucose (FPG), two-hour plasma glucose during a 75 g oral glucose tolerance test (OGTT), or glycated hemoglobin (A1C) may be used for diagnostic testing. OGTT is not commonly used (except during pregnancy) owing to its inconvenience. (See "Gestational diabetes mellitus: Screening, diagnosis, and prevention", section on 'Screening for GDM'.)
The following definitions are consistent with guidelines from the American Diabetes Association (ADA) (table 1 and table 2) [3] and the World Health Organization [4]. The diagnostic criteria were developed based upon the observed association between the glycemic thresholds and the risk for developing retinopathy [5].
Diabetes
Symptomatic hyperglycemia — The diagnosis of diabetes mellitus is easily established when a patient presents with classic symptoms of hyperglycemia (thirst, polyuria, weight loss, blurry vision) and has a random blood glucose value of 200 mg/dL (11.1 mmol/L) or higher. Most patients with type 1 diabetes are symptomatic and have plasma glucose concentrations well above ≥200 mg/dL. Some patients with type 2 diabetes also present with symptomatic hyperglycemia and blood glucose ≥200 mg/dL. (See 'Differentiating the cause' below.)
Asymptomatic hyperglycemia — The diagnosis of diabetes in an asymptomatic individual (generally type 2 diabetes) can be established with any of the following criteria (table 1) [3]:
●FPG values ≥126 mg/dL (7.0 mmol/L). Fasting is defined as no caloric intake for at least eight hours.
●Two-hour plasma glucose values of ≥200 mg/dL (11.1 mmol/L) during a 75 g OGTT.
●A1C values ≥6.5 percent (48 mmol/mol).
In the absence of unequivocal symptomatic hyperglycemia, the diagnosis of diabetes must be confirmed on a subsequent day by repeat measurement, repeating the same test for confirmation. However, if two different tests (eg, FPG and A1C) are available and are concordant for the diagnosis of diabetes, additional testing is not needed [6]. If two different tests are discordant, the test that is diagnostic of diabetes should be repeated to confirm the diagnosis [3]. (Related Pathway(s): Diabetes: Diagnosis of diabetes mellitus or prediabetes in non-pregnant adults.)”
Fasting plasma glucose (FPG), two-hour plasma glucose during a 75 g oral glucose tolerance test (OGTT), or glycated hemoglobin (A1C) may be used for diagnostic testing. OGTT is not commonly used (except during pregnancy) owing to its inconvenience. (See "Gestational diabetes mellitus: Screening, diagnosis, and prevention", section on 'Screening for GDM'.)
The following definitions are consistent with guidelines from the American Diabetes Association (ADA) (table 1 and table 2) [3] and the World Health Organization [4]. The diagnostic criteria were developed based upon the observed association between the glycemic thresholds and the risk for developing retinopathy [5].
Diabetes
Symptomatic hyperglycemia — The diagnosis of diabetes mellitus is easily established when a patient presents with classic symptoms of hyperglycemia (thirst, polyuria, weight loss, blurry vision) and has a random blood glucose value of 200 mg/dL (11.1 mmol/L) or higher. Most patients with type 1 diabetes are symptomatic and have plasma glucose concentrations well above ≥200 mg/dL. Some patients with type 2 diabetes also present with symptomatic hyperglycemia and blood glucose ≥200 mg/dL. (See 'Differentiating the cause' below.)
Asymptomatic hyperglycemia — The diagnosis of diabetes in an asymptomatic individual (generally type 2 diabetes) can be established with any of the following criteria (table 1) [3]:
●FPG values ≥126 mg/dL (7.0 mmol/L). Fasting is defined as no caloric intake for at least eight hours.
●Two-hour plasma glucose values of ≥200 mg/dL (11.1 mmol/L) during a 75 g OGTT.
●A1C values ≥6.5 percent (48 mmol/mol).
In the absence of unequivocal symptomatic hyperglycemia, the diagnosis of diabetes must be confirmed on a subsequent day by repeat measurement, repeating the same test for confirmation. However, if two different tests (eg, FPG and A1C) are available and are concordant for the diagnosis of diabetes, additional testing is not needed [6]. If two different tests are discordant, the test that is diagnostic of diabetes should be repeated to confirm the diagnosis [3]. (Related Pathway(s): Diabetes: Diagnosis of diabetes mellitus or prediabetes in non-pregnant adults.)”
