Blood Samples to monitor Diabetic Dogs and Cats

Blood Samples to Monitor Diabetic Dogs and Cats

Blood samples can be taken to measure blood glucose concentrations or blood insulin concentration.

Measuring blood glucose

  1. Collecting a venous blood sample from a peripheral vein into a fluoride tube. Plasma glucose concentrations are measured in the laboratory (“gold standard”).
  2. Collecting a drop of capillary blood from the ear (pinna), or sometimes a carpal pad or a footpad, and analysing this using a hand-held blood glucose meters (glucometers).
    • Most glucometers measure the glucose concentration in whole blood (not plasma).
    • Readings may vary by as much as 15% from samples submitted to the laboratory.
    • Hand-held meters are reasonably accurate. If a reading seems unusual or does not match the clinical signs, a second reading should be taken or another method used to confirm the blood glucose measurement.
  3. Collecting a drop of capillary blood from the ear (pinna) or a carpal pad or a footpad and analysing this using a blood glucose test strip.
  4. A number of new methods are being tested. These include continuous, less invasive methods of glucose testing, such as using a glucose sensor placed under the skin to record several hundred blood glucose concentrations over a two- to three-day period. This type of device has been tested in diabetic cats.

More information

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Single blood glucose measurements

A single blood sample for glucose measurement can be taken at the time that the blood glucose nadir (lowest concentration is expected). This is particularly used after a dose increase to check that the new dose is not producing hypoglycaemia. Remember that the time to blood glucose nadir is different in each animal. Thus, taking a single sample around 6 to 10 hours after Caninsulin administration is not always going to be appropriate. Single blood glucose measurements are thus most appropriate in animals where the time of blood glucose nadir has been established.

A more accurate way of monitoring the efficacy of treatment is to produce a blood glucose curve.

Measuring blood insulin concentration

Insulin concentrations are not measured routinely in veterinary practice since the majority of diabetic dogs and cats require insulin for treatment and the laboratory methods are not readily available.

It is far more useful to treat the diabetic dog or cat with appropriate doses of insulin, correct diet and a suitable exercise regime and monitor clinical signs and, when required, blood glucose and fructosamine concentrations.

Dose rate adjustments are not made routinely in veterinary practice based on blood insulin concentrations. These are therefore of little practical use for monitoring.