How Do I Make the Diagnosis of Diabetes?

Case Study

Mrs. HR is a 48 year old whom you have screened for diabetes since she is over 40, and has a family history of diabetes.

You decided to use the A1C test.

  • Her first AIC comes back 6.5%

Should you tell her she has Type 2 diabetes?

Yes No
Reveal Answer

You are correct!

Mrs. HR’s first result is in the diabetes range, however, "a repeat confirmatory laboratory test must be done on another day".

Click here to review the Diagnostic Criteria for Diabetes.

Mrs. HR goes for a repeat A1C early the following week.

Her next A1C is 6.9% - the diagnosis of Type 2 Diabetes is confirmed.

No, not yet.

Mrs. HR’s first result is in the diabetes range, however, "a repeat confirmatory laboratory test must be done on another day".

Click here to review the Diagnostic Criteria for Diabetes.

Mrs. HR goes for a repeat A1C early the following week.

Her next A1C is 6.9% - the diagnosis of Type 2 Diabetes is confirmed.

2013 CDA Updated Diagnostic Criteria for Diabetes

FPG ≥ 7.0 mmol/L
Fasting = no caloric intake for at least 8 hours

or

A1C ≥ 6.5% (in adults)
Using a standardized, validated assay, in the absence of factors that affect the accuracy of the A1C (Not for diagnostic use in children, adolescents, pregnant women or suspected type 1 diabetes. Misleading in hemoglobinopathies, iron deficiency, hemolytic anemia, severe liver or renal disease. Altered by aging and ethnicity.)

or

2hPG in a 75-g OGTT ≥ 11.1 mmol/L

or

Random PG ≥ 11.1 mmol/L
Random = any time of the day, without regard to the interval since the last meal

In the absence of symptomatic hyperglycemia, if a single laboratory test is in the diabetes range, a repeat confirmatory laboratory test (FPG, A1C, 2hPG in a 75-g OGTT) must be done on another day. It is preferable that the same test be repeated (in a timely fashion) for confirmation, but a random PG in the diabetes range in an asymptomatic individual should be confirmed with an alternate test. In the case of symptomatic hyperglycemia, the diagnosis has been made and confirmatory test is not required before treatment is initiated. In individuals in whom type 1 diabetes is likely (younger or lean or symptomatic hyperglycemia, especially with ketonuria or ketonemia), confirmatory testing should not delay initiation of treatment to avoid rapid deterioration. If results of two different tests are available and both are above the diagnostic cutpoints, the diagnosis of diabetes is confirmed.

2hPG = 2-hour plasma glucose; FPG = fasting plasma glucose; OGTT = oral glucose tolerance test; PG = plasma glucose

*The Canadian Diabetes Association is the registered owner of the name Diabetes Canada. All content on guidelines.diabetes.ca, CPG Apps and in our online store remains exactly the same. For questions, contact communication@diabetes.ca.