Diabetes mellitus (sugar diabetes) is a common problem. Though diabetic cats may respond well to diet and medication, most cats require daily or twice daily injections of insulin. It can be difficult to determine optimal type, dosage, and frequency of insulin administration. As with diabetic people, each cat is a little different. Some cats will require more or less insulin than another cat. Inadequate dosing can lead to poorly controlled diabetes. Excessive doses can cause weakness, coma, and even death.
One of the best ways to determine the optimal insulin dose in a cat is the glucose curve. In this test, a series of blood glucose (sugar) tests are done over a 12 to 24-hour period. The results of this test facilitate proper insulin dosage and time of insulin administration.
There are no real contraindications to performing this test, but care must be taken if the cat resents the having blood drawn or becomes stressed during the procedure. Stress can increase the blood sugar level, resulting in inaccurate readings and an invalid glucose curve. For this reason, a small blood-sampling catheter may be placed in a vein to allow ready sampling of blood without the need for repeated needle sticks.
What Does a Glucose Curve Reveal in Cats?
Glucose levels are constantly fluctuating, depending on diet, exercise, underlying illness, and the cat’s individual glucose requirements. For diabetic cats, insulin works best when administered at times of highest blood sugar, which typically follows eating. A glucose curve will reveal at what time the cat’s glucose level is the highest and when it is lowest relative to diet and insulin administration. It also helps determine how long the insulin is lasting in your cat, the time of the peak effect and the degree of fluctuation in the blood glucose. This information helps your veterinarian determine determine if your cat is receiving the proper type and dose of insulin. If the glucose levels always register too high or too low throughout the curve, the insulin needs to be adjusted.
How Is a Glucose Curve Done in Cats?
In order to perform a glucose curve, your cat likely will be hospitalized. Since the glucose curve measures the glucose levels over a 12 to 24 hour period. When insulin is given every 12 hours, a glucose curve for 12 hours is recommended. If the insulin is given once daily, a glucose curve that lasts 24 hours is recommended.
A glucose curve can be run in the veterinary hospital or at home. If this test is performed in the veterinary hospital this test is best performed in house where blood tests are run immediately. Outside labs are less often used in determining the glucose curve because of delivery and blood storage issues (which can affect the blood sugar level). During the actual test your cat will rest in a hospital area. A small blood sample is drawn every 2 to 4 hours and the blood sugar level is determined. This information is recorded and graphed over a 12 to 24-hour period. The blood sugar levels are later reviewed relative to food intake and insulin administration. Based on these results, and your veterinarian’s interpretation, the insulin may be altered. Learn more about how to prepare your Cat for a Glucose Curve in the Hospital.
If the blood glucose is consistently high even though the cat is on insulin, the dosage is increased. If the blood glucose is consistently low, the dose of insulin needs to be reduced. If the duration of effect is suboptimal, a different type of insulin may be recommended.
This test can be performed at home using a blood glucometer. For more information go to: How to use a Glucometer for Home Monitoring.
Is a Glucose Curve Painful to Cats?
The only pain involved is associated with the collection of the blood samples. Generally a very small needle is used to pierce the skin and enter a blood vessel to draw the sample. Most cats tolerate this well, but as with people, the pain experienced will vary from individual to individual. Sometimes a small catheter is placed in a vein to minimize the impact of needle sticks.
Is Sedation or Anesthesia Needed for a Glucose Curve?
Neither sedation nor anesthesia is needed in most patients. Cats that resent needle sticks or need sedation for blood draws are not good candidates for a glucose curve. Sedation and stress can impact the glucose readings.