Summary: In a cluster randomized trial of 852 at-risk primary care patients in Hong Kong, a 2-step active opportunistic screening strategy using point-of-care capillary HbA1c (POC-cHbA1c) achieved a much higher screening uptake than usual venous HbA1c practice (76.0% vs 37.5%; OR 7.06, 95% CI 2.47-20.18, p<0.001). More type 2 diabetes (4.2% vs 1.4%; p=0.016) and pre-diabetes (11.8% vs 6.9%; p=0.015) were detected, although the combined diabetes/pre-diabetes effect was only borderline significant (OR 1.99, 95% CI 1.01-3.95, p=0.048).
PICO Summary
| Element | Detail |
|---|---|
| Population | 852 at-risk adults identified by consecutive sampling during primary care consultations; cluster randomized controlled trial across 8 General Out-Patient Clinics, Hong Kong, June 2022 to January 2024. |
| Intervention | 2-step active opportunistic screening using point-of-care capillary HbA1c (POC-cHbA1c), with a confirmatory oral glucose tolerance test offered when preliminary HbA1c was at least 5.6%. |
| Comparison | Usual practice using standard venous HbA1c (vHbA1c) testing requiring multiple clinic visits. |
| Outcome | Screening uptake 76.0% vs 37.5% (OR 7.06, 95% CI 2.47-20.18, p<0.001). Type 2 diabetes detected 4.2% vs 1.4% (p=0.016); pre-diabetes 11.8% vs 6.9% (p=0.015). Combined diabetes/pre-diabetes detection OR 1.99 (95% CI 1.01-3.95, p=0.048). Number-needed-to-screen for one additional diabetes case with POC-cHbA1c versus vHbA1c was 61. |
POC capillary vs venous HbA1c screening
Cluster RCT · at-risk T2D screening · 8 clinics
Point-of-care capillary HbA1c roughly doubled screening uptake versus venous HbA1c and detected more type 2 diabetes and pre-diabetes, though the combined detection gain was only borderline significant.
Expert Commentary
This cluster randomized trial supports point-of-care capillary HbA1c as a pragmatic way to lift screening engagement in at-risk primary care patients, and the verdict is cautiously favourable. The dominant effect was on uptake, which doubled when a single capillary test replaced a venous draw requiring repeat visits, and the higher detection of diabetes and pre-diabetes plausibly follows from more people actually being tested. The main limitation to weigh is that the combined diabetes and pre-diabetes effect was only borderline significant, with a confidence interval reaching down to 1.01 and a p-value of 0.048, so the incremental diagnostic yield beyond improved uptake is modest and statistically fragile. Randomization was at the clinic level, the design was necessarily unblinded, and findings from one Hong Kong public primary care system may not transfer to other settings or assay platforms. Can I use this with my patients? Yes, for clinicians running opportunistic diabetes screening in busy primary care clinics, offering a point-of-care capillary HbA1c is a reasonable way to reduce drop-off, provided the device is quality-assured and abnormal results are confirmed. Wider pragmatic trials across diverse populations would help confirm whether the detection gains hold and translate into earlier treatment.
References
Chan L, Yu EYT, Wan EYF, Wong SYS, Chao DVK, Ko WWK, 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. 2025;23(1):190. doi:10.1186/s12916-025-04007-z