Appendix 8. Guidance for Capillary Blood Ketone Testing in Pregnant Women at Risk of Diabetic Ketoacidosis (DKA)

When to measure blood ketone levels:

  • All women with Type 1 DM who are admitted Unwell/Vomiting. (DKA less likely but not impossible with Type 2 DM, consider testing if 2+ or more urinary ketones).
  • Blood ketone monitoring is NOT for the routine use of women with hyperemesis. Interpretation of Blood Ketones (B-OHB).
\beta OHB mmol/LAction
Below 0.6mmol/l• Normal ketone levels – continue to test blood glucose levels as normal. • Treat for elevated glucose appropriately (discuss with the woman as she is likely to know how to manage this herself or if possible, refer to diabetes team).
0.6 – 1.5mmol/l• Doctor to review. • Ensure adequate fluid intake (if tolerating oral fluids advise at least 200mls water/sugar free fluids every hour). • Consider giving additional rapid acting insulin. • Retest blood glucose and ketones in 1 hour (blood ketones can rise by 1-2mmol/L per hour.
Over 1.5mmol/lRisk of DKA Contact a doctor immediately. • Assess woman for signs of DKA urgently, check U and E's, bicarbonate and pH on venous blood gas analyser. • If confirmed DKA (Bicarbonate < 15.0mmol/L and or pH <7.3) follow Clinical guideline for the management of Diabetic Ketoacidosis (DKA) in adult. Admit for level 2 critical care. • If the pH and bicarbonate are normal the woman is likely to still require additional insulin and fluid replacement via VRIII (or additional subcutaneous doses on advice of diabetes team if possible). • Recheck blood glucose and ketone levels hourly (blood ketones level should fall by 0.5mmol/L per hour).

*In pregnancy DKA can occur with a normal blood glucose level.

Diabetes Mellitus (pre-existing) in Pregnancy Clinical Guideline V3.0