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HbA1c Testing Becoming a New Norm in Healthcare Setting

Jul 23, 2016

HbA1c testing determines diabetes and prediabetes in patients who are not yet diagnosed

More than 8.1 million of the 29.1 million persons in the United States who have diabetes are undiagnosed. Those who are diagnosed are not receiving the necessary treatment or having a regular testing to monitor their glycemic control. 86 million US adults have prediabetes that could advance to diabetes, but only 11% had been told they had that condition. Identifying prediabetes early helps prevent the progression to diabetes. Per the American Diabetes Association, diabetes was diagnosed if HbA1c ≥ 6.5% (140 mg/dl) and prediabetes was diagnosed between 5.7% and 6.4% (117- 137 mg/dl). Hospital, Emergency Department (ED), dental and even all health facilities could become openings for early detection of prediabetes and diabetes. HbA1c determination is the best reference measure of glycemic control. International guidelines recommend its measurement every 3 months in patients who are off target or after therapeutic change. However, there should be two annual measurements in all patients. There are other quick and easy ways HbA1c could be measured and their accuracy is highly satisfactory for estimating control of diabetes mellitus.

The purpose of this study was to investigate the importance of HbA1c testing in all health settings and even in dental clinics to help diagnose diabetes in those who have not yet been diagnosed. In a study conducted at the New York University College of Dentistry, subjects recruited were more than 18 years, did not require antibiotics before dental treatment, and had bloody gums on brushing or flossing. Participants also did not have any cardiovascular, hepatic, immunologic renal, hematologic, organ impairment, been diagnosed of having diabetes or the verge of being diagnosed with diabetes. Two samples of 10 µm blood of Gingival Crevicular Blood and gold standard Finger Stick Blood (GCB and FSB) was collected from qualified subjects. The two samples were then processed for HbA1c testing. Central tendency, dispersion and correlation of FSB HbA1c and GCB HbA1c were measured. This overall was done to determine whether HbA1c testing at the dental visit helps identify people who are at risk of having diabetes or those who already had diabetes, but have not been diagnosed. Statistical method used was the X2 analysis.

Of the 408 eligible subjects, all were paired HbA1c values from FSB and GCB specimen. 56.9% of study participants were female, 23.4% had some college education or completed technical school. 59.9% were between 45 and 64 years and 18.9% were at least 65 years. Each of the 2 HbA1c measures had a mean of 5.9%, median of 5.7%, and a standard deviation of 0.93 and a standard error of the mean of 0.046. 53.2% of the study sample had FSB HbA1c values in the prediabetes or diabetes range. HbA1c with GCB had a 51.5% elevated HbA1c. For patients who had regular visits with dental provider (50.7% vs 17.3%; P< 0.001), those who did not see their primary care physician in the previous year (51.1% vs 25.8%; P=0.026) and those who were never tested for blood glucose or who were tested over a year ago for blood glucose (51.6% vs 16.4% P <0.001). This study found out that adults above 45 years who have never been told they had diabetes benefit more from HbA1c testing at dental offices. Some did not see their PCP the previous year and half of those who have not had blood glucose test had elevated HbA1c reading. Many of those had never been told they had prediabetes or diabetes.

In yet another study, HbA1c measurement was done in ED as a tool to detect undiagnosed diabetes. An observational prospective study was conducted in Spain in a hospital’s ED. Subjects answered a questionnaire on whether they have been diagnosed with diabetes before or had used corticosteroids the past 2 months and if answered yes, were excluded. A blood sample was taken from qualified (n= 187) subjects and the HbA1c value determined. Statistical analysis used is the SPSS 11.0 software. The capillary HbA1c value was 57.8±1.26% (95% CI 5.60-5.97%) and the laboratory level was 6.10±1.12% (95% CI 5.94-6.26%).

In conclusion, HbA1c testing at ED is a reliable, fast and simple way of detecting diabetes and an important diagnostic tool. Also, though the dental office HbA1c test had limitations such as the sample not being random and also patients self-reporting of data, which may have been inaccurate, it was still helpful and gives alternate sites for HbA1c to help detect prediabetes and diabetes in undiagnosed patients. HbA1c should therefore be tested in all healthcare settings since immediate intervention can prevent diabetes.

Practice Pearls:

  • Hospital and ED admissions could become windows of opportunity for an early diagnosis of people with diabetes.
  • Many people visit a dental provider, but not a primary care provider, the dental visit may serve as an opportune site for diabetes screening.
  • Under detection remains a major barrier to prevention of diabetes and associated complications and therefore alternate sites for HbA1c testing is very necessary.


Hng, Tien-Ming et al. “Diabetes Case Finding in the Emergency Department, Using HbA1c: An Opportunity to Improve Diabetes Detection, Prevention, and Care.” BMJ Open Diabetes Research & Care 4.1 (2016): e000191. PMC. Web. 4 July 2016.

Strauss, Sheila M. et al. “The Potential for Glycemic Control Monitoring and Screening for Diabetes at Dental Visits Using Oral Blood.” American Journal of Public Health 105.4 (2015): 796–801. PMC. Web. 4 July 2016.

Gomez Peralta et al. “Point –of –Care capillary HbA1c measurement in the emergency department: a useful tool to detect unrecognized and uncontrolled diabetes”.  International Journal of emergency medicine. 10.1186/s12245-016-0107-6. Web July 4 2016.