Adult DKA and HHS Interpreter (2024 Consensus Criteria)
Adult DKA and HHS Interpreter (2024 Consensus Criteria)
Decide whether an adult in a hyperglycaemic crisis has diabetic ketoacidosis, hyperosmolar hyperglycaemic state, or both, on the 2024 international consensus criteria (ADA, EASD, JBDS, AACE and DTS). The page calculates effective osmolality, grades DKA as mild, moderate or severe, recognises euglycaemic DKA on SGLT2 inhibitors, and shows where the 2024 definitions differ from 2009.
DKA, HHS or mixed?
Glucose, sodium, ketones, pH, bicarbonate → DKA grade, HHS or mixedA 24-year-old with type 1 diabetes has vomited for a day. Glucose 28 mmol/L, sodium 134 mmol/L, blood β-hydroxybutyrate 5.2 mmol/L, venous pH 7.18, bicarbonate 12 mmol/L. Alert, not on an SGLT2 inhibitor.
The 2024 consensus criteria
DKA — D: glucose ≥ 11.1 mmol/L (200 mg/dL) or known diabetes; K: β-hydroxybutyrate ≥ 3.0 mmol/L or urine ketones ≥ 2+; A: pH < 7.3 and/or bicarbonate < 18 mmol/L
HHS — glucose ≥ 33.3 mmol/L (600 mg/dL); effective osmolality > 300 mOsm/kg (or total > 320); β-hydroxybutyrate < 3.0 mmol/L; pH ≥ 7.3 and bicarbonate ≥ 15 mmol/L
DKA severity — mild: pH > 7.25 to < 7.30 or HCO₃ 15–18; moderate: pH 7.0–7.25, HCO₃ 10 to < 15, alert or drowsy; severe: pH < 7.0, HCO₃ < 10, β-hydroxybutyrate > 6.0, stupor or coma
- Effective osmolality
- tonicity; urea is left out because it crosses cell membranes freely
- Euglycaemic DKA
- DKA with glucose below 11.1 mmol/L (200 mg/dL): about 10% of DKA in the consensus
- Mixed
- DKA criteria plus HHS-range glucose and osmolality; the consensus reports overlap in more than a third of crises
Worked example
A 24-year-old with type 1 diabetes has vomited for a day. Glucose 28 mmol/L, sodium 134 mmol/L, blood β-hydroxybutyrate 5.2 mmol/L, venous pH 7.18, bicarbonate 12 mmol/L. Alert, not on an SGLT2 inhibitor.
Effective osmolality = 2 × 134 + 28 = 296 mOsm/kg — not above 300, and glucose is below 33.3, so not HHS
D: known diabetes and glucose 28 (above 11.1) · K: β-hydroxybutyrate 5.2 (3.0 or more) · A: pH 7.18 (below 7.3) → DKA
Grade: pH 7.18 is in 7.0–7.25 and bicarbonate 12 is in 10 to below 15 → moderate; β-hydroxybutyrate 3.0–6.0 does not upgrade it
What changed between 2009 and 2024
| Criterion | ADA 2009 (Kitabchi) | 2024 consensus (Umpierrez) |
|---|---|---|
| DKA glucose | Above 250 mg/dL (13.9 mmol/L) | 200 mg/dL (11.1 mmol/L) or more, or known diabetes at any glucose |
| DKA ketones | Positive ketones (nitroprusside) | β-hydroxybutyrate 3.0 mmol/L or more preferred; urine 2+ or more acceptable |
| Anion gap | Part of the criteria | Not recommended as a first-line diagnostic or resolution criterion |
| HHS osmolality | Effective osmolality above 320 mOsm/kg | Effective above 300 mOsm/kg, or total above 320 |
| HHS bicarbonate | Above 18 mmol/L | 15 mmol/L or more |
Where the UK JBDS guideline differs
| 2024 consensus | JBDS DKA guideline (2023 revision) | |
|---|---|---|
| Acidosis | pH below 7.3 and/or bicarbonate below 18 | pH below 7.3 and/or bicarbonate below 15 |
| Glucose | 11.1 mmol/L or more, or known diabetes | Above 11 mmol/L, or known diabetes |
| Severity | Mild / moderate / severe (Table 2) | Markers for level 2 care: ketones above 6, bicarbonate below 5, pH below 7.0, potassium below 3.5 on admission, GCS below 12, SpO₂ below 92%, systolic BP below 90, pulse above 100 or below 60, anion gap above 16 |
What the 2024 definitions changed
Diabetic ketoacidosis (DKA) and the hyperosmolar hyperglycaemic state (HHS) are the two hyperglycaemic emergencies of adults, and in practice they overlap. In 2024 the American Diabetes Association, the European Association for the Study of Diabetes, the Joint British Diabetes Societies, the American Association of Clinical Endocrinology and the Diabetes Technology Society published a joint consensus (Umpierrez et al., Diabetes Care) that rewrote both definitions.
For DKA the glucose threshold fell from above 250 mg/dL to 200 mg/dL (11.1 mmol/L) — and a history of diabetes now satisfies the glucose criterion at any glucose. That change exists for euglycaemic DKA, which the report puts at about 10% of cases and which is increasingly driven by SGLT2 inhibitors. Ketones should be a measured β-hydroxybutyrate of 3.0 mmol/L or more where possible, and the anion gap was dropped as a first-line criterion because mixed acid-base disorders and the hyperchloraemic acidosis of treatment make it misleading. For HHS the effective osmolality threshold fell from 320 to 300 mOsm/kg, a measured total osmolality above 320 became an alternative, and the bicarbonate floor fell from 18 to 15 mmol/L.
The page therefore needs a number the laboratory does not report — the effective osmolality, 2 × sodium + glucose — and that is its headline. Use the measured sodium for the osmolality; the sodium correction for hyperglycaemia calculator gives the glucose-corrected sodium, which answers a different question (what the sodium will be when the glucose falls). The severity grade is the worst reached by any one variable, because the consensus says not every variable has to be met. Children are graded differently, on ISPAD criteria: use the paediatric DKA severity interpreter. Convert glucose with the glucose unit converter and ketones with the β-hydroxybutyrate unit converter.
What the numbers cannot tell you: the precipitant (infection, missed insulin, myocardial infarction, a new SGLT2 inhibitor), the potassium, which must be known before insulin starts, and the volume deficit. This interpreter supports, and does not replace, clinical judgement.
Frequently asked questions
What are the 2024 DKA diagnostic criteria?
All three of: glucose 200 mg/dL (11.1 mmol/L) or more, or a history of diabetes; β-hydroxybutyrate 3.0 mmol/L or more, or urine ketones 2+ or more; and pH below 7.3 and/or bicarbonate below 18 mmol/L (Umpierrez et al., Diabetes Care 2024).
What is euglycaemic DKA?
DKA with a glucose below 200 mg/dL (11.1 mmol/L). The consensus reports it in about 10% of DKA, and in one series 35% of people on SGLT2 inhibitors who developed DKA had a glucose that low. Because the 2024 glucose criterion accepts known diabetes at any glucose, it now meets the definition.
How is effective osmolality calculated for HHS?
2 × measured sodium plus glucose, both in mmol/L. Urea is left out because it crosses cell membranes and does not hold water outside cells. The 2024 HHS threshold is above 300 mOsm/kg; a measured total osmolality above 320 is the alternative.
Can a patient have DKA and HHS at the same time?
Yes. The consensus reports clinical overlap in more than a third of adults with a hyperglycaemic crisis, with higher mortality than either alone. This page calls it mixed when the DKA criteria are met and the glucose and osmolality are also in the HHS range.
Why does the UK use a bicarbonate of 15 rather than 18?
The JBDS adult DKA guideline (revised 2023) defines acidosis as a bicarbonate below 15 mmol/L and/or pH below 7.3. The 2024 consensus, which JBDS co-authored, uses below 18. A bicarbonate of 15 to 17 is therefore DKA on one definition and not the other.
Related calculators
References
- Umpierrez GE, Davis GM, ElSayed NA, et al. Hyperglycemic crises in adults with diabetes: a consensus report. Diabetes Care. 2024;47(8):1257–1275. Joint ADA, EASD, JBDS, AACE and DTS report; also in Diabetologia. 2024;67:1455–1479. Figure 2 (diagnostic criteria) and Table 2 (severity).
- Kitabchi AE, Umpierrez GE, Miles JM, Fisher JN. Hyperglycemic crises in adult patients with diabetes. Diabetes Care. 2009;32(7):1335–1343.
- Dhatariya KK; Joint British Diabetes Societies for Inpatient Care. The management of diabetic ketoacidosis in adults — an updated guideline from the Joint British Diabetes Society for Inpatient Care. Diabet Med. 2022;39(6):e14788. JBDS 02, revised March 2023.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.