Glucose Curve in Cats
Diabetes mellitus (sugar diabetes) is a common problem. Though diabetic cats may respond well to diet and medication, some do need daily injections of insulin. Difficulty often arises in determining the optimal type, dosage, and frequency of insulin administration. As with diabetic people, each pet is a little different. 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 pet is the glucose curve. In this test, a series of blood glucose (sugar) tests is done over a 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 animal 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?
Glucose levels are constantly fluctuating, depending on diet, exercise, underlying illness, and the pet's individual glucose requirements. For diabetic pets, insulin works best when administered at times of highest blood sugar, which typically follows eating. A glucose curve will reveal at what time the pet's glucose level is the highest and when it is lowest relative to diet and insulin administration. This information helps your veterinarian determine the best time to give the insulin. A glucose curve will also help your veterinarian determine if your pet 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 order to perform a glucose curve, your pet likely will be hospitalized. Since the glucose curve measures the glucose levels over a 24 hour period, this test takes about 24 hours to complete although abbreviated curves are done sometimes. 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 pet will rest in a hospital area. A small blood sample is drawn every 2 to 4 hours and the sugar level is determined. This information is recorded and graphed over a 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.
If the blood glucose is consistently high even though the pet 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.
Is a Glucose Curve Painful?
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 pets 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. Pets 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.