Spot Capillary HbA1c Testing Boosts Type 2 Diabetes Detection in High-Risk Patients, Study Finds

"Compared to traditional venous HbA1c testing, POC-cHbA1c testing led to twice the screening uptake, delivered quicker results, reduced the need for follow-up visits, and identified more previously undiagnosed cases of type 2 diabetes," the researchers reported in BMC Medicine.

The delayed diagnosis of type 2 diabetes increases the risk of complications, making the high number of undiagnosed cases in Hong Kong a growing public health concern. Point-of-care capillary HbA1c testing offers a convenient, timely, and comparably accurate alternative to traditional venous HbA1c (vHbA1c) testing for diabetes screening. However, evidence from randomized trials is limited.

Linda Chan, The Bau Institute of Medical and Health Sciences Education, The University of Hong Kong, Hong Kong SAR, China, and colleagues evaluated the effectiveness of a two-step active opportunistic screening approach using POC-cHbA1c versus usual care with vHbA1c and multiple clinic visits in identifying type 2 diabetes among at-risk patients in primary care. The main outcomes included comparing diabetes detection rates and testing uptake between the two groups.

For this purpose, the researchers conducted a cluster randomized controlled trial across eight General outpatient clinics between June 2022 and January 2024, using a two-step active opportunistic screening approach. In the first step, 852 at-risk individuals were identified during routine primary care visits based on specific inclusion and exclusion criteria. In the second step, these patients underwent either point-of-care capillary HbA1c (POC-cHbA1c) testing in the intervention group or venous HbA1c (vHbA1c) testing in the control group.

Those with HbA1c levels ≥5.6% were offered a confirmatory oral glucose tolerance test. Clinics were randomized using a computer-generated sequence, and multilevel logistic regression assessed the impact of the intervention on testing uptake, accounting for patient factors and clinic-level clustering.

The following were the key findings of the study:

• The uptake rate for POC-cHbA1c testing was significantly higher than for vHbA1c (76.0% vs 37.5%; OR = 7.06).
• POC-cHbA1c identified a greater proportion of type 2 diabetes cases (4.2% vs 1.4%).
• Detection of pre-diabetes was also higher with POC-cHbA1c (11.8% vs 6.9%).
• Combined detection of type 2 diabetes and pre-diabetes was more likely with POC-cHbA1c (OR = 1.99).
• The number needed to screen to identify one additional case of type 2 diabetes using POC-cHbA1c versus vHbA1c was 61.

"The study highlights the strong potential of POC-cHbA1c testing as an effective screening strategy for type 2 diabetes in primary care. With significantly higher uptake and improved detection rates compared to traditional venous HbA1c testing, POC-cHbA1c can help expand screening coverage, accelerate diagnosis, and support earlier intervention among at-risk individuals," the authors concluded.

Reference:

Chan, L., Yu, E.Y.T., Wan, E.Y.F. et al. Improving type 2 diabetes detection among at-risk individuals – comparing the effectiveness of active opportunistic screening using spot capillary-HbA1c testing and venous HbA1c testing: a cluster randomized controlled trial. BMC Med 23, 190 (2025). https://doi.org/10.1186/s12916-025-04007-z