Blood Samples as a Monitoring Tool

Blood samples can be taken to measure blood glucose concentrations.

Measuring blood glucose

1. Collect a venous blood sample from a peripheral vein into a suitable tube.

2. Collect a drop of capillary blood from the ear (pinna), or sometimes a carpal pad or a footpad, and analyse this using a hand-held blood glucose meter (glucometers).

• Readings may vary by as much as 15% from samples submitted to the laboratory.
• Hand-held glucometers 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 concentration.

3. Collect a drop of capillary blood from the ear (pinna) or a carpal pad or a footpad and analyse 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

See Publications:

• Wess G, Reusch C (2000). Capillary blood sampling from the ear of dogs and cats and use of portable meters to measure glucose concentration.
• Casella M, Wess G, Reusch CE (2002). Measurement of capillary blood glucose concentrations by pet owners: a new tool in the management of diabetes mellitus. J Am Anim Hosp Assoc. 2002 May-Jun; 38(3): 239-45

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. The time to blood glucose nadir is different in each animal. Thus, taking a single sample between 6 and 10 hours after insulin administration is not always going to be appropriate.

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