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Home Blood Glucose Testing for Diabetic Cats
Susan Williamson and Dr. Margie Scherk

December 9, 2001


The movie on Home Blood Glucose Testing is available in several versions for:

VIN Members

VSPN Members

Your Clients with Diabetic Cats

KathyJames: Welcome, everyone, to Sunday Night Rounds. Tonight's topic is "Home Blood Glucose Testing for Diabetic Cats" I'm pleased to introduce Susan Williamson, a senior student at VA-MD and Dr. Margie Scherk, whom you all know from the Internal Medicine Feline Boards.

SusanWilliamson: Thanks Kathy! I became involved with feline diabetes, in December 1999, when my cat Maxwell was diagnosed with diabetes mellitus. I studied textbooks and VIN to help me learn about his disease and how to handle it. Another place I started looking was the web. While I had experience with diabetic pets through my work in an animal hospital, I wanted to learn about the day to day living with a diabetic from other people in that situation. On the internet, I found several great sites where I could talk to other owners in the same situation and learned that I wasn't alone with my new concerns. I also learned about home testing and decided that since owners with no medical background were home testing, I could too. This seemed to be ideal as well because Max's attitude was messing our curves at work. So I read the method from the internet, talked it over with Dr. William E. Monroe here at school, and proceeded.

Home testing showed me I needed to change the type of insulin he was on and helped me regulate him for the first time since his diagnosis. Since then, home testing has helped me monitor his regulation with curves and provided quick and easy information on his BG in situations where I suspected he was hypoglycemic. It's been useful this year as Max's care has been sort of random, thanks to a wildly erratic schedule, to make sure he is still somewhat regulated ;)

The video started as part of the Dratted Diabetic Cat course given in April of this year. We got onto a discussion of home testing, and someone wished for a video of how to do it. I said I would record my method if I had a camera, and Margie and Kathy contacted me about doing just that. The timing was kind of rough... it was right in the middle of final exams and carried over into senior year misery, but we managed to get the taping and the editing completed. A HUGE thanks to everyone at VIN involved in this project, particularly Mike and Kathy! I'm thrilled with the results and I sure hope it is used! The video is designed for owners, but you and your staff can easily learn the method and demonstrate it "live."

I have taught several clients how to home test and have discussed it with many others. I generally start by empathizing with them about having a diabetic cat. From there, I ask about how the injections themselves are going and how they learned to give the injections. Then I say something like "Since you learned how to give injections so well, I would like to offer you a tool you can use, with your veterinarian's help, to better manage Fluffy's diabetes. I test my cat's blood glucose at home, and it has been a great help. You can learn how to do this too, and it is no more painful or trouble than an insulin injection for Fluffy to tolerate. I'll show you how and give you a list of items you need from the pharmacy. I found home testing to be a tremendous help for my cat, and I think it will help your pet too". At first, many recoil, but then I re-emphasize the fact that they learned to give injections and that this is very similar and can be just as easy to do. Then I show them, usually on their own cat or a clinic cat. When they see that the cat sits still for it and often keeps on purring, they are often willing to try it.

I ask them to call if they have questions, and I refer them to the websites I learned from, if they have internet access. If they don't, I've printed pages for them to take home and read. Now with the video available, I'll play that for them and offer a copy for them to put on their home computer, and I suppose somebody could figure out how to record it on a VCR from a computer if necessary.

SabraMyers: Susan, Have you really seen cats be very accepting of this procedure? I saw the video, and your own cat didn't flinch, but I'm just wondering if other cats take it as well.

SusanWilliamson: I've tried it on non-diabetics as well, and most don't flinch. The acceptance rate seems to be pretty good. Of course, I do have one cat of my own I wouldn't try it on -- she'd probably try to eat me!

AlexandraSoltan: Do you start right away discussing home monitoring at the time of diagnosis or ease them in slowly?

SusanWilliamson: Generally slowly, after they've learned how to give injections and feel OK with that. It would be a lot to dump on them right at first as the diagnosis can be scary for an owner.

AlexandraSoltan: That's what I was thinking too.

KellyStDenis: My concern with these home monitoring techniques is that some clients will start to change insulin doses on their own (I've had it happen), how do you avoid this?

SusanWilliamson: I try very hard to emphasize that managing a diabetic is a team effort. Anyway, some owners could probably learn to make minor adjustments of the dose on their own, but it is certainly a risk. I think Margie has a little more info on this later.

KellyStDenis: The minor adjustments don't bother me, its the major ones!

MichaelRichards: I want my clients to learn to make the minor adjustments and spend a lot of time working towards this goal with them; almost all can understand the theory behind the dosing.

SusanWilliamson: Absolutely, thanks Michael.

DuaneSteward: The answer to Kelly StDenis' question is provider-client communication. There is a new age upon us for communication that we must learn to use for such questions.

KellyStDenis: Of course, if we are able to maintain good contact with our clients, we should be able to avoid any dose changing catastrophes

SusanWilliamson: Let me tell you about some websites that I found helpful in my diabetes education and refer clients to. My favorite website has been It is the most complete reference on the web for laypersons on diabetes mellitus, both canine and feline. The information is generally accurate and written so it is understandable by the pet owner, although it is not run by a veterinarian. It covers everything from general information about diabetes and insulin to selecting meters to coping with multiple-problem pets (i.e. DM and CRF).

Another website is This is kind of a wacky site for owners to get together and laugh about life with a diabetic cat. The information I used to learn to home test was recently moved here, but I was unable to find it on the site last weekend. There is also information here about ordering 100% beef PZI from Europe, and clients will ask about that sometimes.

PZI insulin information can be found at Blue Ridge Pharmaceuticals: You used to be able to download the order form there, but now you have to call and have one faxed to you.

I found helpful with articles on making injections and home testing easier, although I learned very quickly to filter through the discussion on the associated message board for accuracy!

My advice to clients on using information from message boards or e-mail lists has been to always discuss items written there with the vet in charge of the case before altering treatment. However, I do encourage participation in message boards or e-mail lists, simply because of the support available to owners with newly diagnosed pets. It really can be overwhelming to be told one's pet is diabetic, and the support offered on the net can help owners cope with the ups and downs of this disease.

Speaking of e-mail lists, there are two list serves available for owners to join. The pet diabetes site has instructions on joining a list, and the list is generally excellent with many members. The list owner is very good about making sure that the discussions stay on track and strongly recommends that all suggestions from other list members be discussed with the pet's veterinarian.

Another list is the Muffin list. It has a worldwide membership and is also generally good about staying on topic and recommending veterinary input. The Muffin list can be found at On that website is a list of questions called "Do's and Don'ts" that I like to fill out for each owner of a newly diagnosed pet that answers questions such as what to do if the pet won't eat, vomits a meal, the symptoms of hypoglycemia and so forth. These questions seem to be the ones that pop up on the e-mail lists the most, especially on weekends when most hospitals are closed. One drawback is that neither list has formal veterinary contact, as the CRF list does with our own Kathy James. As a student, I've worked to provide accurate general information on various topics (e.g. what a fructosamine test is, etc.) to the list members, just not lately with senior year demands being quite heavy.

Other sites are available and can be found with any search engine. Since about 50% of Americans have internet access either at home or work, more and more of our clients use the net as a source of information, good or bad. You can use this to help you by providing sites that offer accurate information and encourage your clients to educate themselves and be an active part of the team in their pet's health care.

SabraMyers: Anyway of getting the video on VHS?

SusanWilliamson: I'm sure somebody more electronically literate than me...

PaulPion: We will work with Susan and see what we can do :)

SusanWilliamson: I think I'm ready to turn this over to Margie now, for a discussion of incorporating the results of home testing into diabetes management.

MargieScherk: Thank you, Susan! You are an inspiration in your dedication to helping others :-) Now that Susan has given you some background and you have had a chance to ask her questions, I would like to go over situations in which I have clients perform BG curves at home as well as when it is appropriate for them to do spot BG measurements. We'll also look at interpreting some curves to see what they are telling us and what changes we might want to make in response to that information.

The first thing we have to be sure of is that the cat actually does have diabetes (poor glycemic control) before we start trying to regulate him/her. Because cats are exquisitely sensitive to epinephrine-released glucose to help them achieve great bursts of speed in hunting, anything causing epinephrine release will, of course, cause hyperglycemia. When serum glucose exceeds the renal threshold, glucosuria occurs, even in a non-diabetic cat. So, how do we verify that the kitty is, in fact, diabetic?

We can either repeat the blood glucose and urine glucose determinations, which run the risk of causing more stress, or request that a fructosamine level be run on the previously collected sample. Fructosamine measures the protein-bound glucose levels over the preceding 10 - 20 days. Currently, serum fructosamine is a test that is run by most veterinary diagnostic laboratories. Similarly, glycated hemoglobin is synthesized in red blood cells in an irreversible reaction between glucose and amino acids of the hemoglobin. As glycated hemoglobin levels reflect glycemic control over the preceding 60-90 days, fructosamine detects successful management and changes to management earlier than glycated hemoglobin.

In regulating a cat with diabetes, I will start the kitty on insulin as well as make dietary recommendations. I generally start with between 1-3 units of insulin q12h and work up from there. There is no magic ceiling maximum dose of insulin that can be given, despite what textbooks suggest (of course there is a maximum for a given patient). The dose required is dependent on the individual's own lack of pancreatic beta cell production or peripheral insulin receptor impairment. Obviously, each cat with pancreatic diabetes has a different degree and amount of pancreas affected; similarly, those cats who have peripheral receptor impairment will also vary as to how much resistance there is. The correct dose of insulin is the dose that causes the clinical signs of diabetes (PU/PD, polyphagia and weight loss) to resolve.

Because we can't "pick" this dose out of thin air, we have to monitor the effect of insulin on an individual cat's blood glucose. This means taking measurements every hour. Yup, I mean q1h. Less than this frequency will leave room for false interpretation of what happens between the readings. Bear this in mind when we look at some graphs which I copied from an excellent article out of Veterinary Forum Sept 25, 2000; Vol 17, No 9. p42.

The VIN staff is going to send everyone a web tour now, so you can view the graphs when we discuss them a little later.

KarenJames: VIN members use this link:

VSPN members use this link:

MargieScherk: All of these graphs have the times plotted at four hour intervals. This does not mean that you should only measured the values that infrequently! You will miss the highest and lowest values. In addition to insulin, I ask the clients to offer their kitty a high protein, low carbohydrate diet, preferably canned/tinned, as this helps to regulate glycemic control much better than high fiber diets in cats. We give the client diary sheets to teach them how to monitor and become observant of the following important parameters: date, time, dose insulin given, demeanor, BM, appetite, urine quantity, water volume drunk, and comments.

We send them home and follow-up with phone calls until we are sure that they feel comfortable with the injections and the diary. We want them to bring their kitty back for the first BG curve in clinic at 7-10 days and I will adjust insulin dose according to this curve. I will repeat curve and perform fructosamine 10-14 days later and adjust dose again. In general, and I tell clients up front, it will take about 5-6 curves before we find the correct dose for a given cat. Some important parameters to note on your (or a client's) curve are:

- time till nadir,

- value of nadir, and

- duration of insulin action.

These values will help you to determine what type of insulin to use, when to change insulin type. It helps to determine if insulin dose is too high or too low. We repeat curve visits every 10-14 days until the kitty is regulated OR with a dedicated client I encourage them to do curves at home q 14 days and fax/email/call the results in, consult with client to adjust dose. Remember to charge for this! (We'll look at specific curve types at the end of this session if time allows.)

BarbDeyell: What type of insulin do you generally start with?

MargieScherk: I am in Canada, so I have Caninsulin available and start with that insulin. If I didn't have Caninsulin available, I'd use Humulin NPH in cats, insulin is needed BID :-)

SabraMyers: Do you have any information on whether the Purina DM is coming out in a dry form? I have a cat who will not eat the canned food, so we have him on w/d.

MargieScherk: It is available in dry and is excellent. All of my cats eat it preferably over any of the other about 8 kinds of dry around my house -- w/d is not a choice I would make. I'd offer a growth formulation - we want to avoid high fiber diets and focus on high protein.

SabraMyers: So is the dry DM acceptable, then? You said that you prefer a canned diet.

MargieScherk: Yes.. it is for those cats who won't eat canned :-)

SabraMyers: Okay, thanks. :)

JessicaRankin: I read that glucose curves change day to day and that your recommendation one day could be completely different the next day. What is your opinion on that?

MargieScherk: I have checked that in a few of my own cats and have found that not to be true. There are some small variations, true, but not such that I would make different recommendations :)

Okay. When else do I have clients check BGs at home? I ask them to do spot checks before administering insulin if cat is not behaving normally. This way they may detect hypoglycemia and avoid insulin overdose. Once the kitty is stable, we recall them check fructosamine and urinalysis (to check for early bacterial urinary tract infection) q 3-4 months. If kitty changes in any of the diarized parameters, they are to contact their veterinarian and take appropriate action based on their conversation with you or the emergency clinic.

For stable, home regulated cats, I like to ask clients to perform a curve every 2 months, but I still want to check fructosamine and urinalyses 3-4 times a year. Home urine stick measurements are okay for ketones, but are unreliable for glucose, i.e. for making insulin dose adjustments. They are always inaccurate for leukocytes and nitrates, so can't be used by a client to determine if their cat has a bacterial urinary tract infection. Let's look at some curves and what they tell us!

Please go to Figure 1. This is an image of the BG sticker I had made for use in my clinic. In Canada we use mmol/l for glucose measurements, so normal is 3.3-6.9 mmol/l (50-125 mg/dl). Yet I am showing that "in clinic ideal range" is 5.5-10 mmol/l (100-180 mg/dl) to try to compensate for the effects of stress.

MargieScherk: Now, Figure 2: This is an ideal BG curve. Note that it is bimodal. With twice daily (q12h) insulin, you'd aim for this curve. The insulin effect has a duration of 10-12 hours, the nadir (lowest point) is at 6 hours and its value is 120 mg/dl (6.6 mmol/l)

In Figure 3 we see the very different curves for three different patients (dogs in this case) receiving the same dose and type of insulin. Note how dissimilar these curves are. This probably reflects differences in absorption and metabolism of the insulin. The dog represented with the green curve has poor absorption. The red, this is a good dose although the action of the insulin is shorter than ideal. The blue curve represents a Somogyi rebound hyperglycemia. Each of these interpretations would warrant a different therapeutic decision.

Figure 4: what have we here? That's right! This is a non-responsive curve. What do we want to recommend?

AlexandraSoltan: Insulin resistance?

MargieScherk: Sure! it could be resistance or any other reason that is allowing the insulin to not get into the cat's system and effectively do what it is supposed to do :-)

AlexandraSoltan: Owner injecting into the fur :)

MargieScherk: It could be poor absorption, poor administration, damaged insulin - exactly! :-) anyone else? What recommendation would you make?

SabraMyers: My thought would be to switch insulin type, but could also be any of the above, right?

MargieScherk: Right! :-) If I was certain that the client was giving the insulin properly and the insulin wasn't damaged (non refrigerated, etc), I'd recommend changing the kind of insulin we are using (e.g. From humulin to a different kind if increasing the dose of the present insulin didn't have the desired effect. What would you expect the fructosamine value to be in this case?

AlexandraSoltan: Should be elevated

MargieScherk: BINGO! It would be elevated as the overall glycemic control is inadequate.

Next. Figure 5. In this case, the action of the insulin is too short. You could consider changing the insulin type to one which is longer acting. The fructosamine will probably be elevated as the BG levels will be above normal range for most of the day.

MargieScherk: Okay, onward. Figure 6: This shows a delayed onset of insulin action. Suggestions as to course of action?

AlexandraSoltan: Use a mixed insulin - like Caninsulin :-)

MargieScherk: Right... you could... main thing would be to change the insulin to one with a more rapid speed of onset. What about the fructosamine level? Do you think with this delayed onset the fructosamine would be high, normal or low?

  • NickNail: High
  • AlexandraSoltan: Could be normal possibly
  • BethShannon: Normal

MargieScherk: (remember, fructosamine is like an avg of the glycemic control over a long period) I would expect it to be high (but it could maybe be normal)

Figure 7: This shows poor glycemic control and the need for BID insulin rather than SID. What would the fructosamine level look like?

  • LaurelPinales: high
  • ChuckEdgerly: high
  • NickNail: high

MargieScherk: Bravo! :-) It would be elevated. Let's look at Figure 8: This shows an insulin overdose. What action will you take as far as insulin adjustments?

  • LaurelPinales: Lower dose, maybe change type
  • NickNail: Change Insulin type and lower the dose
  • AlexandraSoltan: delay any insulin until BG rises

MargieScherk: Perfect :-) you guys are right on top of this! :-) Sure. You'd decrease the dose of insulin. What would the fructosamine level likely be in this situation? (Most definitely hold off with any insulin in the short term, Alex!)

NickNail: Low

SabraMyers: Wouldn't it be normal? measures over a period of time

MargieScherk: Nick, this is an interesting one... it could be low, but it would depend on how long the insulin lasted and how much of the day the blood sugar is above normal, so it could even be HIGH! This is why you need to look at curves AND fructosamines...not just one or the other. Let's go to the last image:

In Figure 9 we are looking at the "Somogyi effect". This is a rebound hypoglycemia-induced hyperglycemia. If the cat's blood glucose drops too low, the body reacts by releasing catecholamines (epinephrine), glucagon, glucocorticoids and growth hormone. This causes a rapid release of glucose into the serum causing this rebound to occur. It is important to not be tempted to increase the insulin dose in these individuals, as this would accentuate the problem and eventually cause a hypoglycemic crisis. "Spot checks" of blood glucose levels should be avoided as they can be misleading and can mask a rebound effect, and be misinterpreted as needing more insulin.

I actually go through all of this with my clients...this way, they don't try to interpret them on their own nor do they make dose adjustments without contacting me first. :-)

ChuckEdgerly: I've had cases with this going on due to client 'dosing' and the does of insulin just keeps going up.

MargieScherk: It can get really ugly when they play with the doses on their own. I have had to "fire" one client over it. Okay, we have looked at a number of different types of curves and how we might interpret them, what dose/insulin adjustments we might make and what the fructosamine may read as.

NickNail: Are the figures available to download?

MargieScherk: Kathy, can one print these figures? Otherwise, they are in the Vet Forum issue mentioned :-) They are very helpful teaching tools

KathyJames: They won't be at the best resolution for printing really

MargieScherk: I'd like to quickly summarize what I went over, before we call it a night.

... Confirm diagnosis (fructosamine, history)

... Start insulin and diet and diary

... Diary = date, time, dose insulin given, demeanor, BM, appetite, urine quantity, water volume drunk, comments

... BG curve in clinic at 7-10 days and adjust dose

... Repeat curve and perform fructosamine 10-14 days later and adjust dose

... Types of curves (images)

... Note time till nadir, value of nadir, duration of insulin action

... Helps determine what type of insulin to use, when to change insulin type

... Helps determine if insulin dose is too high or too low

... Do this q 14 days until regulated OR

... Have client do curves at home q 14 days at home and fax/email/call the results in, consult with client to adjust dose (Charge for this.)

... Ask client to do spot checks before administering insulin is cat is not behaving abnormal

... Once stable, check fructosamine and urinalysis (to check for early bacterial urinary tract infection) q 3-4 months

... Home urine stick: okay for ketones, unreliable for glucose insulin adjustments and inaccurate for leukocytes, nitrates

That's all from me... thanks for attending! I hope this has been helpful. Many thanks esp to Susan! :-)

PaulPion: Thank you Susan and Margie!

SusanWilliamson: And thanks to Margie!

AlexandraSoltan: Yes thanks guys

ColeenHarman: Thank you!

BarbDeyell: thanks!

NickNail: Very good session Margie, Thanks

ChuckEdgerly: Thanks, Good night!

SabraMyers: Thanks. :)

JessicaRankin: Thank you everyone!

Total Joins: 57; SusanWilliamson MargieScherk PaulaMack RobinSyverson RafaelBohorquez KevinReed NanetteWalkerSmith1 PongpaoHosathitam ColeenHarman ChuckEdgerly KathyJames NathanLissant KarenJames SabraMyers AlexandraSoltan DianeOlszowy BethShannon NickNail PhyllisWebster BarbDeyell JohnBerggren PaulPion GeraldBlackburn MarkVernon MatiasAramburu LaurelPinales DonnaStephensManley KathySell AnthonyNanton ThomasHanna JenniferKoehler CarolHillhouse MichaelRichards (LynneBoggs SusanCampolongo1 JessicaBaron JessicaRankin RobTope HerbBetts JessicaBaron MelissaCichocki CecilJohnson ClaytonKilrain NancyBeeman KevinBannister GregUpton KellyStDenis RichardLevine JessicaRankin LeeAnnWood DuaneSteward ShawnBartosh TanithTyrr JanetTriplett CindyCamp FrankMarcoBrianBaumgard

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