investigations

Last reviewed 01/2018

Investigations carried out in DKA patients include:

  • serum glucose level
    • usually greater than 250 mg/dL (13.9 mmol/L)
  • arterial blood gas measurement
    • pH varies from 7.00 to 7.30
    • measurement of venous pH is recommended for monitoring treatment
  • serum electrolytes (electrolytes on blood gas machine give a guide until accurate results available)
    • bicarbonate level - <18 mmol/L (18 mEq/L)
    • serum sodium level - usually low
    • serum potassium - may be low, normal, or elevated
    • magnesium – usually low but can be normal
  • blood urea nitrogen, creatinine levels
    • usually elevated because of dehydration and decreased renal perfusion
  • serum ketone level
  • urinalysis
    • confirms the presence of glucose and ketones
    • positive for leukocytes and nitrites in the presence of infection
  • anion gap
    • elevated anion gap >10-12 mmol/L (>10-12 mEq/L)
    • anion gap = ([Na mmol/L] – ([Cl mmol/L] + [HCO3 mmol/L])
  • serum osmolality
    • greater than 320 mmol/kg (320 mOsm/kg) ()
    • plasma osmolality = 2 ([Na mmol/L] + [K mmol/L]) + [Urea mmol/L] + [glucose mmol/L]

Other investigations carried out according to the clinical indications are:

  • ECG – to assess the effect of potassium status; rules out ischemia or myocardial infarction
  • chest x-ray - if pneumonia or pulmonary disorder is suspected
  • urine and blood cultures - if infection is suspected
  • PCV & FBC - leucocytosis is common in DKA and does not necessarily indicate sepsis (1,2,3)

Note:

  • bedside monitoring has been shown to be helpful in the clinical situation of diabetic ketoacidosis
    • portable blood ketone analysers, analysers for blood gas and electrolyte measurement if  available will give results within a few minutes
    • therefore, glucose, ketones and electrolytes, including bicarbonate and venous pH, should be assessed at or near the bedside

Reference:

Related pages:

non-ketotic diabetic acidosis