Quest Diagnostics presented research results at the American Diabetes Association’s 2026 Scientific Sessions, which occurred in New Orleans on June 5-8.  The study, presented as a poster, was titled “Increases in Glycated Hemoglobin (HbA1c) Testing Following Expanded Medicare Screening Coverage.”

The researchers, which included a diabetes expert from the University of Pittsburgh, shared insights into increases in glycated hemoglobin (hbA1c) testing following expanded Medicare screening coverage for the test.

Prior to 2024, Centers for Medicare and Medicaid Services (CMS) coverage for diabetes screening was limited to fasting glucose and an oral glucose tolerance test, both of which have disadvantages. 

Fasting glucose measurement can be problematic because some patients with impaired glucose tolerance or diabetes may have glucose levels within the reference range at the time of the measurement. And, for some patients, traditional oral glucose tolerance tests can be too time and labor intensive.

On January 1, 2024, CMS expanded coverage to include use of hbA1c tests for diabetic screening.

To measure the impact of the expansion, the study analyzed hbA1c testing patterns between two periods: January 1, 2022 through September 30, 2022 (“Period 1”) and January 1, 2024 through September 30, 2025 (“Period 2”), performed by Quest on patients >65 years without any prior diagnosis of type 1 diabetes (T1D) or type 2 diabetes (T2D).

There was a statistically significant increase of 30.1% in mean monthly testing volume between Period 1 and Period 2 (p < 0.0001). This increase may indicate that clinicians were aware of the Medicare policy change noted above.

Another notable finding was an increase in the percentage of patients who tested positive for prediabetes (defined as HbA1c 5.7-6.4%) from 37% in period 1 to 55% in period 2.

The study’s strengths included the large volume of testing from a national diagnostic laboratory in both periods. Limitations were a lack of clinical data and, as such, an inability to confirm whether positive screens led to confirmatory testing or initiation of therapy.

In closing, these findings suggest that the Medicare policy change, along with the demonstrated increase in hbA1c testing for diabetes screening, may help inform those 65 years of age and older of a new diagnosis of prediabetes. Approximately 500,000 to 600,000 new cases of diabetes occur every year within this age group. With knowledge of a prediabetes diagnosis, earlier intervention may be possible to prevent disease progression and complications – empowering more patients with insights to make health proactive, connected, and personal.