Ren Q, Lv X, Yang L, et al. - Researchers conducted this population-based epidemiological survey to assess A1c performance for diabetes screening in high-altitude polycythemia compared with a population with a high proportion of people living in an oxygen-deficient environment. The cities Lhasa and Shigatse were chosen for this analysis. Participants in the study were 1,401 Tibetan adults [mean age was 44.3 ± 15.0 years] without known diabetes. In Tibet, the optimal HbA1c cutoff for diabetes detection was 46 mmol/mol (6.4%). Red blood cell count has been an independent risk factor for elevated HbA1c, and high-altitude polycythemia may affect HbA1c's predictive ability.