Nigeria

HbA1c test: what the percentage means and the diabetes threshold

HbA1c measures the proportion of your haemoglobin that has glucose attached to it. Because red cells live around three months, it reflects average blood sugar over that period rather than the morning you happened to visit the lab.

HbA1c interpretation

HbA1cCategoryApprox. average glucose
Below 5.7%NormalBelow 117 mg/dL
5.7 – 6.4%Prediabetes117 – 137 mg/dL
6.5% and aboveDiabetes range140 mg/dL and above
Below 7.0%Common treatment target once diagnosedSet with your clinician

No fasting required

HbA1c needs no preparation, which makes it the easier test to add to an existing blood draw. It is also less affected by a stressful morning or an imperfect fast than a single glucose reading.

When HbA1c misleads

Anything that shortens red cell survival lowers HbA1c falsely — sickle cell disease and trait, other haemoglobinopathies, recent blood loss, haemolysis, pregnancy and iron deficiency all distort it. Given how common sickle cell trait is in Nigeria, an HbA1c that disagrees with your glucose readings should prompt a fasting glucose or oral glucose tolerance test rather than reassurance.

A rising HbA1c inside the normal range still counts

A move from 5.3% to 5.6% is still 'normal' but it is the wrong direction. Logging each result here plots the trend, which catches drift years before a single value crosses a threshold.

Keep reading

Educational only. Reference ranges are general guidance and are not a diagnosis — take your results to a qualified clinician.

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