Blood Glucose Profiles (Curves)
by Holly R. Frisby, DVM 
Drs. Foster & Smith
Veterinary Services Department

NOTE:Other articles related to diabetes mellitus in cats
are listed at the end of this article.

A blood glucose profile (or curve) is a graph of blood glucose levels over time.
It is the most effective way to determine the type, dose, and frequency of administration of insulin. necessary to keep the blood glucose at acceptable levels. Each cat responds very differently to insulin, and so the appropriate insulin therapy must be determined for each individual cat. In addition, a cat's insulin needs may change dramatically over time, so blood glucose profiles may need to be performed periodically for the life time of the cat. 

Blood glucose profiles are necessary because each cat reacts differently to the types of insulin, dosage and intervals at which insulin is given. By performing a blood glucose profile, we can determine if an insulin was effective, when the peak effect occurred (i.e., when the glucose level was at its nadir (lowest point), how long the effect lasted, and the degree of fluctuation in the glucose level. Changes can then be made in the type of insulin, the dosage or the dosing intervals in order to maintain the blood glucose at the optimal level throughout a 24 hour period. In some cases, up to five or more blood glucose curves may need to be performed before a satisfactory regimen is determined. Because of the cost, abbreviated profiles (fewer samples) are sometimes used. In addition to the blood glucose profile, the response of the cat is noted. The amount the cat is eating, drinking, and urinating; activity level; and weight all help determine if the insulin regimen is effective. 

How is a blood glucose profile performed?
To perform a blood glucose curve, a blood sample is taken to check the blood glucose level, the cat is fed and the insulin is administered. Additional blood samples are taken at regular intervals throughout the day to monitor the blood glucose level. It is recommended that a cat be on that specified insulin dose for 4-7 days before the glucose profile is performed to give her body time to equilibrate. 

Diet and exercise greatly affect the cat's need for insulin. During the regulation process, it is important to feed the cat the same food, in the same amounts, at the same time, that it will be fed at home. The cat's activity level should also mirror what she will be doing at home. The timing of the administration of insulin should also be consistent with when the owner will be able to give the insulin at home. 

How is the blood glucose measured?
The glucose level in the blood is determined through laboratory testing. This may occur in your veterinarian's office, or the sample may be sent to an outside laboratory. Since we want to take only very small amounts of blood from the cat, the use of a hand-held glucometer at your veterinarian's office is recommended. To use this device, several drops of the blood sample are placed on a chemically-impregnated paper strip. A chemical reaction occurs that changes the color of the strip depending upon the amount of glucose present. The wavelength of the color is read by placing the strip in the glucometer. 

Why can't we just measure the amount of glucose in the urine?
Glucose will appear in the urine of cats if the blood glucose level goes over 260-310 mg/dL; the normal blood glucose level is 55-160. (In dogs, glucosuria occurs if the blood glucose level exceeds 180-220 mm/dL.) A determination of blood glucose tells us what the blood glucose level is at that particular time. A urine glucose test does not tell us what is going on at the time the urine sample was obtained; it is an average of the glucose level in the urine which was formed since the cat last urinated - that could be 8 or more hours ago. Insulin dosages should NOT be changed based solely on urine glucose levels. 

What special problems do cats pose when performing a blood glucose profile?
Some cats may have stress-induced hyperglycemia (high blood sugar). Under stress (such as being in a veterinary office), these cats can rapidly develop high blood glucose levels (300-400mg/dL). The fact a cat is hospitalized and having her blood drawn can dramatically change her blood sugar levels. The dose of insulin needed to "regulate" her while she is stressed in the veterinary hospital may be much different than the dosage necessary to maintain a good blood glucose level when she is comfortably at home. 

In addition, it is sometimes difficult to get cats to eat well when they are hospitalized. In performing a glucose curve we want the cat to eat the same amount of food it would at home, at the same time it would at home. Eating must also be coordinated with when the insulin is administered. We generally want the cat to eat at approximately the same time the insulin is given. 

For these reasons, many veterinarians will hospitalize a diabetic cat for up to six days before performing a blood glucose curve. This acclimates the cat to the hospital, the cat will hopefully be eating normally, and the results of the glucose profile should be more reflective of the insulin needs of the cat once she goes home. Many things may be done to decrease the cat's stress, including the use of intravenous catheters or very small needles to draw the blood. If the results are to be accurate, cats cannot be sedated or tranquilized while performing a blood glucose profile. 

For more information:
Other topics related to diabetes mellitus in cats include: 
The Signs, Diagnosis and Types of Diabetes Mellitus in Cats 
Regulating and Monitoring a Diabetic Cat Using Insulin 
Handling, Storing and Administering Insulin 
Treating a Diabetic Cat with Oral Blood-Glucose-Lowering Drugs (Glipizide) 
Dietary Therapy in Diabetic Cats 
Longterm Complications of Diabetes Mellitus in Cats 
Terms Commonly Associated with Diabetes Mellitus 

References for articles related to diabetes in cats
Diehl, KJ. Long-term complications of diabetes mellitus, Part II: Gastrointestinal and infections. In Greco, DS; Peterson, ME (eds) The Veterinary Clinics of North America Small Animal Practice: Diabetes Mellitus. WB Saunders Co., Philadelphia PA; 1995: 731-752. 

Ford, SL. NIDDM in the cat: Treatment with the oral hypoglycemic medication, glipizide. In Greco, DS; Peterson, ME (eds) The Veterinary Clinics of North America Small Animal Practice: Diabetes Mellitus. WB Saunders Co., Philadelphia PA; 1995: 599-616. 

Garcia, JL; Bruyette, DS. Using oral hypoglycemic agents to treat diabetes mellitus in cats. Veterinary Medicine. 1998 (August); 736-742. 

Greco, DS; Broussard, JD; Peterson, ME. Insulin therapy. In Greco, DS; Peterson, ME (eds) The Veterinary Clinics of North America Small Animal Practice: Diabetes Mellitus. WB Saunders Co., Philadelphia PA; 1995: 677-690. 

Ihle, SL. Nutritional therapy for diabetes mellitus. In Greco, DS; Peterson, ME (eds) The Veterinary Clinics of North America Small Animal Practice: Diabetes Mellitus. WB Saunders Co., Philadelphia PA; 1995: 585-598. 

Lutz, TA; Rand, JS. Pathogenesis of feline diabetes mellitus. In Greco, DS; Peterson, ME (eds) The Veterinary Clinics of North America Small Animal Practice: Diabetes Mellitus. WB Saunders Co., Philadelphia PA; 1995: 527-552. 

Miller, E. Long-term monitoring of the diabetic dog and cat: Clinical signs, serial blood glucose determinations, urine glucose, and glycated blood proteins. In Greco, DS; Peterson, ME (eds) The Veterinary Clinics of North America Small Animal Practice: Diabetes Mellitus. WB Saunders Co., Philadelphia PA; 1995: 571-584. 

Muñana, KR. Long-term complications of diabetes mellitus, Part I: Retinopathy, nephropathy, neuropathy. In Greco, DS; Peterson, ME (eds) The Veterinary Clinics of North America Small Animal Practice: Diabetes Mellitus. WB Saunders Co., Philadelphia PA; 1995: 715-730. 

Nelson, RW. Diabetes mellitus. In Birchard, SJ; Sherding, RG (eds): Saunders Manual of Small Animal Practice. WB Saunders Co., Philadelphia PA; 1994;249-256.

Nelson, RW; Feldman, EC. Insulin resistance: Etiologies and diagnostic approaches. Presented at the 81st Annual Convention of the Wisconsin Veterinary Medical Association. Madison WI, October 20,1996.

Nelson, RW; Feldman, EC. Treatment strategies in the management of canine and feline diabetes mellitus. Presented at the 81st Annual Convention of the Wisconsin Veterinary Medical Association. Madison WI, October 20,1996.

Norsworthy, G. Choosing the right insulin type and dosage for diabetic cats. Veterinary Medicine. 1998 (April);314-318. 

Norsworthy, G. Does this cat have diabetes? Veterinary Medicine. 1997 (November;947-949. 

Norsworthy, G. Dysregulation in diabetic cats: Part 3. Veterinary Medicine. 1999 (May);431-432. 

Norsworthy, G. Peculiarities in diabetic cats. Veterinary Medicine. 1997 (December);1026-1027. 

Norsworthy, G. Performing a blood glucose curve in a diabetic cat. Veterinary Medicine. 1998 (May);425-428. 

Norsworthy, G. Recognizing and treating hypoglycemia in diabetic cats. Veterinary Medicine. 1998 (August);707-711. 

Norsworthy, G. The initial steps in treating diabetic cats. Veterinary Medicine. 1998 (March);223-226. 

Norsworthy, G. Using oral hypoglycemic drugs to treat diabetic cats. Veterinary Medicine. 1998 (July);616-617. 

Norsworthy, G. What to consider before you treat a diabetic cat. Veterinary Medicine. 1998 (January);31-34. 

Peterson, ME. Diagnosis and management of insulin resistance in dogs and cats with diabetes mellitus. In Greco, DS; Peterson, ME (eds) The Veterinary Clinics of North America Small Animal Practice: Diabetes Mellitus. WB Saunders Co., Philadelphia PA; 1995: 691-714. 

Plotnick, AN; Greco, DS. Home management of cats and dogs with diabetes mellitus: common questions asked by veterinarians and clients. In Greco, DS; Peterson, ME (eds) The Veterinary Clinics of North America Small Animal Practice: Diabetes Mellitus. WB Saunders Co., Philadelphia PA; 1995: 753-759. 

Struble, AL; Nelson, RW. Non-insulin-dependent diabetes mellitus in cats and humans. The Compendium on Continuing Education for the Practicing Veterinarian. 1997;19(8):935-944. 

© 2000 Drs. Foster & Smith, Inc.
Reprinted as a courtesy and with permission from PetEducation.com (http://www.PetEducation.com)

On-line store at http://www.DrsFosterSmith.com

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Beta cells: Cells of the pancreas which are responsible for making insulin 

Blood glucose profile (curve):

A graph of blood glucose levels over time. At the time of insulin injection, and at regular intervals throughout the day, the level of glucose in the blood is determined through laboratory testing. 

Glipizide: An oral medication that can be used to control blood glucose levels in some diabetic cats who still have some insulin production. 

Glucosuria: glucose in the urine. (Also called glycosuria) 

Glycogen: A storage form of glucose in the body. 

Hyperglycemia: higher than normal blood glucose level 

Hypoglycemia: lower than normal blood glucose level 

Insulin: A hormone produced by the pancreas which is necessary for glucose to be able to enter the cells of the body and be used for energy. 

Insulin dependent diabetes mellitus (IDDM): A form of diabetes in which so little insulin is produced that supplemental insulin must be given for the animal to live. Also called Type I diabetes mellitus. 

Insulin resistance: A condition in which the blood glucose level remains higher than it should at an insulin dosage of 2 units/pound of body weight per day in cats. 

Ketoacidosis: A life-threatenting condition in which ketones, which result from the breakdown of fat for energy, accumulate in the blood stream and the pH of the blood decreases. 

Nephropathy: Abnormal functioning of the kidney. 

Neuropathy: Abnormal functioning of nerves. 

Non-insulin dependent diabetes mellitus (NIDDM): A type of diabetes mellitus in which although the blood glucose levels are higher than normal, they are not immediately life-threatening, and the animal can survive without supplemental insulin. Also called Type II diabetes. 

Oral hypoglycemic agent: A medication, given by mouth, which lowers the level of glucose in the blood. Example: glipizide 

Plantigrade stance: Standing and walking with the hocks on or almost touching the floor. 

Polydipsia: excessive thirst resulting in excessive drinking 

Polyphagia: excessive ingestion of food 

Polyuria: excessive urination 

Regulation: Using insulin to maintain the blood glucose level of an animal within the acceptable range. 

Somogyi effect: A condition in which the blood glucose level increases if too much insulin is given. It occurs when insulin causes the blood glucose level to go so low it stimulates the production of other hormones in the body such as epinephrine which promote the breakdown of glycogen (the chemical compound which the body uses to store glucose) and increases the blood glucose level above normal. It is also called rebound hyperglycemia or insulin-induced hyperglycemia. 

Stress-induced hyperglycemia: A condition in cats in which the blood glucose level becomes abnormally high when the animal is stressed, e.g., in the veterinarian's office. 

Type I diabetes: A form of diabetes in which so little insulin is produced that supplemental insulin must be given for the animal to live. Also called insulin dependent diabetes mellitus (IDDM). 

Type II diabetes: A type of diabetes mellitus in which although the blood glucose levels are higher than normal, they are not immediately life-threatening, and the animal can survive without supplemental insulin. Also called non-insulin dependent diabetes mellitus (NIDDM). 

© 2000 Drs. Foster & Smith, Inc.
Reprinted as a courtesy and with permission from PetEducation.com (http://www.PetEducation.com)

On-line store at http://www.DrsFosterSmith.com

Free pet supply catalog: 1-800-323-4208