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Endocrinology General Medicine Strong — NICE NG28, WHO 2011

HbA1c Converter

Interprets HbA1c in mmol/mol (IFCC). Classifies diabetes control and identifies diagnostic thresholds.

Used in: Diabetes & DKA

To convert from %: HbA1c (mmol/mol) = (HbA1c% − 2.15) / 0.0915

Score interpretation

Normal 0–41

HbA1c < 42 mmol/mol (< 6.0%): Normal glycaemia. Not diabetic or pre-diabetic.

→ Routine check as clinically indicated. Lifestyle advice if risk factors present.

Pre-Diabetes / High Risk 42–47

HbA1c 42–47 mmol/mol (6.0–6.4%): Pre-diabetes / high risk of developing T2DM.

→ Intensive lifestyle intervention: weight loss ≥5%, 150 min exercise/week. Annual HbA1c monitoring. Consider metformin if high risk.

Diagnostic of Diabetes / Target Achieved 48–57

HbA1c 48–57 mmol/mol (6.5–7.4%): Diagnostic threshold for T2DM (if ≥48 on two occasions or with symptoms). NICE target for most patients on treatment: ≤48.

→ Newly diagnosed: confirm with repeat test unless symptomatic. On treatment: NICE target ≤48 for most. Consider intensification if above target.

Above Target 58–74

HbA1c 58–74 mmol/mol (7.5–8.9%): Above NICE target. Risk of microvascular complications.

→ Intensify hypoglycaemic therapy. Address adherence. NICE 2023: if HbA1c >58 mmol/mol, consider GLP-1 receptor agonist or SGLT2 inhibitor.

Poor Control ≥ 75

HbA1c ≥75 mmol/mol (≥9%): Very poor glycaemic control. High risk of acute and chronic complications.

→ Urgent medication review. Consider insulin if not already on it. Refer to diabetes specialist nurse or clinic. Screen for DKA triggers.

Interpretation bands for the HbA1c. Apply clinical judgement and local guidance.

References

Related

Curated clinical cross-links plus same-class fallbacks.

Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.