BACKGROUND: This pilot study examines whether a novel diabetes screening approach using gingival crevicular blood (GCB) could be used to test for hemoglobin A1c (HbA1c) during periodontal visits.
METHODS: Finger-stick blood (FSB) samples from 120 patients and GCB samples from those patients with adequate bleeding on probing (BOP) were collected on special blood collection cards and analyzed for HbA1c levels in a laboratory. The Pearson correlation coefficient was used to measure correlation between FSB and GCB HbA1c values for 75 paired FSB and GCB samples. A receiver-operator characteristic curve (ROC) analysis was performed to determine an optimal GCB HbA1c criterion value for a positive diabetes screen.
RESULTS: For the 75 paired samples, the Pearson correlation coefficient was 0.842. The ROC analysis identified a criterion value of 6.3% for the GCB HbA1c test with high sensitivity (0.933) and high specificity (0.900), corresponding to FSB HbA1c values ≥6.5% (in the diabetes range). Using this GCB HbA1c criterion value for 27 additional paired samples, in which there was an unidentified component observed to coelute within the elution window of GCB HbA1c in the laboratory, there was agreement between FSB and GCB values for 24 of the pairs according to whether both were within or outside of the diabetes range.
CONCLUSION: Using a criterion value of 6.3%, GCB samples are acceptable for HbA1c testing to screen for diabetes in most persons with BOP at the GCB collection site.