investigations

Last reviewed 01/2018

Simple investigations are often sufficient to confirm the clinical diagnosis of diabetes mellitus:

  • urinalysis for glucose and ketones: it should be remembered some reagent strips give a false negative result for glucose in the presence of significant ketonuria
  • plasma glucose measurement: reagent strip and laboratory measurement of random and/or fasting plasma glucose

Other investigations include:

  • plasma bicarbonate and pH measurements
  • urea, creatinine and electrolyte measurements
  • glycosylated haemoglobin
  • white cell count +/- cultures as a screen for precipitating infection

Investigations performed for research purposes may include:

  • anti-insulin and anti-islet cell antibodies
  • C-peptide levels following carbohydrate challenge

It is important to remember to minimise venesection in the newly diagnosed diabetic; the last thing one wishes to create is a phobia of needles.