Discrepancies between HbA1C and fasting blood sugar (FBS) levels can be concerning. Dr. Pranav Ghody, a consultant endocrinologist at Wockhardt Hospitals in Mumbai, explains that while an HbA1C of 4.0 suggests good average blood sugar control, an FBS of 121 mg/dL indicates a prediabetic state. This situation can arise from various factors, including the dawn phenomenon, which leads to natural increases in blood sugar during early morning hours due to hormonal changes. Other reasons for the mismatch could include lab variations or pre-test conditions such as stress, poor sleep, or recent illness. Dr. Ghody emphasizes the importance of not relying on a single measurement and suggests repeating tests for confirmation. Additionally, lifestyle modifications—such as balanced meals, stress management, and good sleep hygiene—are essential for maintaining healthy blood sugar levels. If discrepancies persist, further evaluations like post-meal blood sugar monitoring may be necessary.