HbA1c
%
Unit
4.0
Reference range — low
Labs vary; read yours against its own range
5.6
Reference range — high
Labs vary; read yours against its own range
HbA1c reflects your average blood sugar over roughly three months. Values of 5.7–6.4% are generally read as prediabetes and 6.5% or above supports a diabetes diagnosis when repeated — thresholds your clinician interprets in context.
Conditions that change red-cell lifespan (anaemia, recent transfusion, pregnancy) can distort the number, which is why an unexpected result is confirmed rather than acted on alone.
Before you worry
Reference ranges differ between laboratories, and single values are interpreted in context. An out-of-range number is a reason to talk to your clinician, not a diagnosis.