Study suggests that diabetes can be accurately diagnosed from a single blood sample

1. Single blood sample looking at fasting glucose and HbA1c was a key predictor of subsequent diagnosis of diabetes.

2. Results suggest that a single sample blood test may be used in clinics in the confirmation of undiagnosed diabetes.

Evidence Rating Level: 2 (Good)

Study Rundown: The number of patients affected by diabetes continues to grow in North America. As a result, it is important to have simple and effective diagnostic tests for this condition. At the moment, current clinical definitions of diabetes require sequential blood work, where glucose levels and other blood markers are examined. The authors of this study evaluated whether a single-sample test could be used to confirm undiagnosed diabetes. In general, it was found that this single blood test had a high positive predictive value (PPV) for diagnosis of diabetes. This study had several limitations. First, there were some limitations regarding the self-reported diabetes cases during follow-up during this study, Furthermore, a longer study time point and additional information on repeated testing could have benefitted interpretation of study results.

Click to read the study in Annals of Internal Medicine

Relevant Reading: HbA1c as a Diagnostic Test for Diabetes Mellitus – Reviewing the Evidence

In-Depth [prospective cohort]: The authors of this study aimed to see whether a single sample blood test, looking at fasting blood glucose and HbA1c levels, could be utilized in the diagnosis of unconfirmed diabetes mellitus. They conducted a prospective cohort study, including a total of 12 268 participants without diagnosed diabetes. These patients came from the Atherosclerosis Risk in Communities (ARIC) study. The definition of confirmed undiagnosed diabetes used in the study included elevated fasting glucose levels (≥ 7.0 mmol/L [≥ 126 mg/dL]) and HbA1c (≥ 6.5%) from a single blood sample. Overall, the study results suggested that this blood test was associated with a high PPV for diabetes confirmation. Among the patients with elevated levels of fasting glucose of HbA1c at baseline in the study, this diabetes test definition had moderate sensitivity (54.9%) and high specificity (98.1) for identification of diabetes cases at 5 years. Specificity increased to 99.6% by 15 years.

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