HbA1c Interpretation (mmol/mol)
Interprets HbA1c in IFCC mmol/mol: diagnostic thresholds and NICE treatment targets. To convert to DCCT %: % ≈ 0.0915 × mmol/mol + 2.15.
Score interpretation
HbA1c < 42 mmol/mol (< 6.0%): Normal glycaemia. Not diabetic or pre-diabetic.
→ Routine check as clinically indicated. Lifestyle advice if risk factors present.
HbA1c 42–47 mmol/mol (6.0–6.4%): non-diabetic hyperglycaemia — high risk of type 2 diabetes (NICE PH38).
→ Intensive lifestyle intervention: weight loss ≥5%, 150 min exercise/week. Annual HbA1c monitoring. Consider metformin if high risk.
HbA1c ≥ 48 mmol/mol (6.5%) is the diagnostic threshold for type 2 diabetes (repeat to confirm if asymptomatic; WHO 2011). In treated diabetes NICE NG28 targets 48 mmol/mol (lifestyle or a drug that does not cause hypoglycaemia) or 53 mmol/mol (a drug that can).
→ Newly diagnosed: repeat the test to confirm unless symptomatic. On treatment: compare with the individual NICE target (48 or 53 mmol/mol) and consider intensifying if above it.
HbA1c ≥ 58 mmol/mol (7.5%): NICE NG28 advises intensifying treatment.
→ Intensify treatment (NICE NG28); address adherence and lifestyle. If very high or symptomatic, review urgently, consider insulin and refer to the diabetes team.
Interpretation bands for the HbA1c. Apply clinical judgement and local guidance.
References
- NICE NG28. Type 2 diabetes in adults: management. 2015 (updated 2022).
- NICE PH38. Type 2 diabetes: prevention in people at high risk. 2012 (updated 2017).
- WHO. Use of glycated haemoglobin (HbA1c) in the diagnosis of diabetes mellitus. 2011.
Related
Curated clinical cross-links plus same-class fallbacks.
- Insulin (IV Infusion — ICU Glucose Control) · Insulin — ICU Glucose Management
- Dextrose 50% (Glucose 50%) · Glucose Supplement
- Dextrose 10% IV · IV glucose solution (hypoglycaemia treatment)
- Glucose · Carbohydrate / hypoglycaemia treatment
- Potassium chloride with glucose · IV fluid (potassium + dextrose)
- Potassium chloride with glucose and sodium chloride · IV fluid (mixed)
- Diabetic Ketoacidosis (DKA) · JBDS 2013 / Joint British Diabetes Societies; NICE NG17
- Adult Hypoglycaemia (Treated Diabetes) · JBDS-IP (2023): Hospital Management of Hypoglycaemia
- Adrenal Crisis · Society for Endocrinology Emergency Guidance (2024)
- Type 2 Diabetes Management · NICE NG28 2022
- Hyperthyroidism Management · BTA / ETA 2018
- Adrenal Insufficiency · Society of Endocrinology / ESE 2016
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.