Glucometer

Most caregivers who test their pets’ blood glucose levels use human glucometers. These two documents compare the features of various glucometers and link to the Internet sites for the manufacturers. Ease of use ratings and more specifics can be found at the link below for all major US brands.

Buying a Glucometer

You can buy a glucometer at a brick-and-mortar or Internet pharmacy that sells diabetic supplies. You can expect to pay $25 to $50 for a glucometer in the US. However, manufacturers often have rebate certificates that can make the meter free. Check the advertising supplements in your newspaper for pharmacies that have rebate offers or “buy the strips, get the meter free” deals. Internet pharmacies also often offer similar rebates and deals.

It is the strips, not the meters, that are the pricey part of hometesting blood glucose. Consider checking the price and eBay availability of strips before you decide on a meter. However, even though the strips may be pricey, the cost and stress of performing blood glucose tests at home is far less than at the vet. Also, testing before every insulin shot protects your pet from an accidental overdose of insulin (hypoglycemia) and can provide valuable analytical information for you and your vet to make dosing decisions.

Examples of blood glucose meters specifically designed for pets include the Alphatrak glucometer , the iPet glucose meter and the Advocate PetTest Glucose Meter (by Pharma Supply).

Read carefully when shopping eBay for test strips; some people are offering expired or very soon to be expired ones. Test strips use chemicals (called reagents) to perform this job. The dating on the strips, like insulin, means this is what the manufacturer considers the last date by which the strips can perform properly. Using expired strips can mean false or inaccurate blood glucose testing results. Many of the newer meters automatically detect if an expired strip has been inserted and will not proceed with the test. Also be aware that there are counterfeit test strips on the market for some glucometer models. This FDA information details how counterfeit strips for One Touch brand glucometers have been discovered--in various pharmacies and stores throughout the US. This link gives details; here you will see not only the test strip lot numbers but can visit links which detail the counterfeit characteristics of each lot.

Choosing the best kind

Factors to consider for choosing your own include:

• Blood drop size
• Ease of use
• Precision (how repeatable are the results)
• Accuracy (how correct are the results)
• Error behavior (can the meter give a bad reading?)
• Data upload ability (for recording and plotting readings over time)

Dogs are less resilient to the effects of hyperglycemia than cats, and therefore canine caregivers may need to be more exacting about the accuracy of their readings. Cats may be harder to get large blood drops from painlessly, so feline caregivers may be more concerned about the size of blood drop required, and the error behavior.

For any pet, it is important to get a meter that takes only a small amount of blood and that has “sipping” strips that automatically draw the blood up into the strip. Sipping (aka "capillary action") strips are much easier to use for pets and use less blood. When a meter requires less blood, the process is easier and quicker.

Some meters require a blood drop of one microliter or less: the size of a pinhead. A couple use only 1/3 of a microliter. For comparison's sake, one microliter equals 0.001 milliliter or 0.001 cubic centimeter; it is about the size of a ball-point pen tip. The link below gives the amount of blood sample needed for all glucometers currently sold in the US in graph form.

Some meters can give a false reading when the blood sample is not full. Others will refuse to give any reading until it is full.

Many meters have additional “bells and whistles” such as multiple daily alarms for curving and the ability to upload readings to an electronic format (such as a spreadsheet) for easy logging. If you'd like to upload insulin logs, ask the retailer or the manufacturer's support line for a "data cable" for the meter -- it's often free if you ask!   Most meters on the market now have a built-in data port.

Whole Blood vs Plasma Readings

Glucose levels in plasma (a component of blood) are generally 10-15% higher (even more after eating) than glucose measurement in whole blood. All of our home devices actually measure the glucose content of whole blood. Most lab testing measures the glucose content of the plasma.

Many currently marketed meters automatically display their readings (through a math algorithm built into the device) as plasma equivalent. Thus allowing one to better compare their meter results to those of lab testing. It's important that you know whether the meter you're using displays readings as whole blood equivalent or plasma equivalent.

Meters for animals

Some people prefer to buy animal validated meters, like these , especially for canine patients. This page presents the opinion of the developer of one animal-specific meter as to why human glucometers are not appropriate for use on animals. On the other hand, some recent testing by volunteers from the FDMB found no significant difference in accuracy between the Abbott AlphaTrak and leading human glucometers, on feline blood.

Animal-specific systems are far more expensive than glucometers and test strips made for humans. A vial of 50 test strips for one model is $75. Alterations are made to the human test strips to produce a result.

When the system appeared in 2004, the FreeStyle meter was offered with the altered strips. Those animal-validated strips are no longer available, but caregivers can purchase/use standard FreeStyle test strips in that meter. The currently offered meter with animal-validated strips is the EasyGluco. You cannot use the EasyGluco strips in the FreeStyle meter. Many from the Canine Diabetes Message Board have tried the animal-validated strips; no one except the person mentioned in link below was able to obtain consistent, reliable results.

In March, 2006, Abbott began marketing its AlphaTrak animal-validated glucometer. It basically operates similarly to those above, with the validation process being accomplished through obtaining blood glucose test results over a period of time from dogs and cats and validating through averages of them as compared to Antech Laboratories' results. Over 200 dogs and 200 cats were tested to validate the AlphaTrak meter--in each group, only slightly more than 50 were diabetes patients.

In the AlphaTrak system, it's the meter which is validated; the two systems above are validated through the test strips. Knowing that the validation was applied to the meter and not the strips, it's interesting to note that Abbott's latest glucometer for people, the FreeStyle Freedom described below, also is able to use the tiny 0.3 microliter blood sample as well. All blood testing was with venous, not capillary, blood.

These threads from FDMB offer both a graphed and a numerical comparison of the Abbott AlphaTrak glucometer for pets against some of the more popular meters made for humans.

You can compare the variance between your home meter and the vet's lab testing easily enough. Take your meter with you when vet blood tests are being done. By using a drop of the same blood sample, you will be able to see how much difference (if any) there is between your vet's equipment and your home meter. Regardless of the brand, most find their glucometer is quite accurate when compared this way. (Note that some vets, when testing blood glucose and not also other blood values, use a human glucometer instead of their lab equipment.)

Reading your glucometer

This chart shows what readings to expect and what to aim for.

In the US, blood glucose is measured in milligrams per deciliter (mg/dL). Almost everywhere else, including the UK, Canada, and Australia, blood glucose is measured in millimoles per liter (mmol/L). You should make sure that your meter “reads” using your country’s system. A blood glucose reported in mg/dL is 18 times larger than the same value reported as mmol/L. For example, a mg/dL reading of 300 would convert to a mmol/L reading of 16.7.

This FDMB link has a calculator to convert numbers between the two systems and as well as a conversion chart. Some may prefer the cleaner look and feel of the ChildrenWith Diabetes blood sugar converter. Those who post information on the Feline Diabetes Message Board primarily reside in the United States; therefore, blood glucose values most often are posted as mg/dL, or are given in both systems.

Tip: If a blood glucose value has a decimal component (e.g., 7.7), or is under 25, it is most likely a value being reported in mmol/L.

Factors Which Can Affect Readings

Hemocrit The amount of red blood cells in the blood. Someone with higher hemocrit values will test lower than someone with normal hemocrit levels. Anyone with anemia or an anemia-related disorder will test higher than someone with normal hemocrit values. If you know there is a possibility for either higher or lower than normal hemocrit values due to concurrent disease, discuss their possible impact on blood glucose readings with your health care provider. Dehydration--Severe dehydration can cause inaccurate false low results. Fats/Lipids--Excess cholesterol or triglycerides can also produce false meter readings. Other Substances can affect your test results. They include uric acid (A natural substance in the body which can be more concentrated in those with diabetes.), glutathione (an anti-oxidant known also as "GSH"), and ascorbic acid (Vitamin C). Read the information for your meter to determine what substances, if any, may affect its accuracy--discuss these concerns with your doctor. Altitude, Temperature, Humidity are all capable of having unpredictable effects on blood glucose readings. Both the meter and test strip inserts have more information about these issues. Store meter(s) and test strips according to their respective instructions. Generic Test Strips are less-expensive copies of the branded ones. If and when manufacturers change anything about their meter(s) and/or branded test strips, generic manufacturers are not always advised of these changes. The type, amount(s) or concentration of the chemicals (called reagents) used in the testing process can change. Glucometers are sensitive to these changes and as a result, blood glucose readings may be inaccurate with the generic strips .

At present, the only generic style strips available in the US are produced for the One Touch Basic, One Touch II and Profile meters by UniCheck.

Meter Ranges

Learn the range of your particular meter. The broad values meters measure are from 0-600 mg/dL, but the values are not linear throughout them. Very low or very high readings need to be confirmed; it may be that your meter needs calibration and this is what's causing the abnormal readings.

Meter Accuracy

In the US, all glucometers designed for use in humans must meet FDA approval standards to be marketed as medical devices. In short, this means that every brand sold must meet at least the minimum FDA requirements. Home glucometers and test strips designed for use in animals are not required to meet  any approval standards before they are placed on the market. There is no requirement that veterinary medical devices be FDA-approved prior to marketing them.

FDA's glucometer standards date back to 1997. Here are the basics as they were written then; the use of the term "future" would likely apply to all glucometers currently available.

The consensus document expressed the following performance goals: a) "The goal of all future Self Monitoring Blood Glucose (SMBG) systems should be to achieve a variability (system plus user) of 10% at glucose concentrations of 30-400 mg/dL 100% of the time. However, the panel is aware that the accuracy required for clinical management has not been rigorously defined.", b) "With current systems, SMBG measurements should be within 15% of the results of the reference measurements.", c) "Approximately 50-70% of individuals who receive some sort of formal training are capable of obtaining a result within 20% of the reference method; however, performance may deteriorate over time."

Taking Care Of Your Meter

Doing quality control checks of it regularly means being able to depend on its accuracy. See the instructions which came with your brand of meter. An electronic test of the meter means it is working properly; in some models the accuracy can also be checked in this way. Others rely on control solution tests. Some manufacturers include this in their meter kits. The control solution(s) have expiration dates, just as the test strips do. If it is used out of date, the test results may not be accurate. More control solution can be ordered--either from the manufacturer itself or your pharmacy. Many people with diabetes or their caregivers don't heed this advice and test their glucometers regularly.

Some meters require cleaning, while others do not. Some which need to be cleaned can be cleaned by the owner but others can be cleaned only by the manufacturer. Read the information pamphlet(s) which came with your meter for this information. Speficially for alphatrak glucometer , a manual available from their site for download or from the package itself provides specific details on how care and maintain your blood glucose meter.

Choosing a Glucometer

• Compare Price and Read Reviews on Glucometers
• Choices by Petdiabetes.org
• Choices by ChildrenWithDiabetes.com
• FDMB members glucometer informal survey
• Hope's glucometer accuracy tests graphed and discussed here and here.
• Article by David Mendosa discussing an upcoming report on a study by US Center for Disease Control (CDC) researchers on the variability of currently marketed glucometers and strips
  The researchers plan to issue a report in 2006. There seems to be a lot of variance between meters AND their testing strips.
• Good Meter Comparison Chart
• Graph Comparison--Amount of Blood Sample Needed for All Current US Meters--Childrenwithdiabetes.com
• Meter Testing Times-Childrenwithdiabetes.com
• Test Strip Price Comparisons-2006-Childrenwithdiabetes.com
• Best Glucose Meters that give accurate results

Manufacturer links

• Lifescan One Touch Ultra
• Bayer Glucometers
• Freestyle Glucometers

Apps

• PredictBGL for Pets

Further Reading

• Evaluation of 6 Portable Blood Glucose Meters in Dogs-ACVIM 2008, Oral Presentations-Page 30, Abstract #95