American Diabetes Association Complete Guide to Diabetes: The Ultimate Home Reference from the Diabetes Experts

CHAPTER 7

Self-Monitoring Tools

• Lancets

• Test Strips

• Blood Glucose Meters

• Continuous Glucose Monitors

• Logbooks

• Ketone Tests

• Where to Buy Supplies

Now that you’ve read about the importance of monitoring your blood glucose, you probably want to know exactly how to measure your blood glucose. There are a handful of tools that will help you accurately and easily measure your blood glucose every day. These tools are now smaller and more sophisticated than anyone would have dreamt of 30 years ago.

New products are always being developed, so keep in mind that this chapter just covers the most essential tools. Every year the American Diabetes Association’s magazine Diabetes Forecast publishes a Consumer Guide for patients that describes the latest devices, as well as most devices currently on the market. The Consumer Guide is published in print and online, and it is a patient’s best resource for researching blood glucose monitoring tools (http://forecast.diabetes.org/consumerguide).


Essential Tools

Lancet: A device that pricks the skin with a small needle to obtain a blood sample.

Test Strip: A strip (with a blood sample) that is inserted into a blood glucose meter.

Blood Glucose Meter: A small, portable machine used to display blood glucose readings on a digital display.

Blood Glucose Log: A record of your blood glucose readings over time. Some people prefer a paper log, whereas others prefer a digital log.


Lancets

Lancets allow you to take a sample of blood with minimal discomfort and optimal discretion. The spring-loaded device contains a needle or lancet, a way to select how deep the needle goes, and a release button. You’ll want to use the shallowest poke possible to draw blood. This hurts less and causes less scarring on your fingers.

Many blood glucose meters come with lancing devices. However, there are quite a few lancets on the market, so shop around if you don’t like the one that came with your meter or if you want more than one. Some allow you to prick sites other than your fingers. Others are designed for people who have trouble drawing blood or who have sensitive or calloused skin. Still others have retractable needles or easy disposal systems. Different lancets produce different sizes of blood drops. Make sure the device you are considering will help you get a drop of blood that is large enough for your meter.

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Lancets are sterile the first time only, so don’t share lancets or lancing devices. Lancets can become dull after multiple uses, making future fingersticks more painful, so change them when needed to fit your comfort level.

Not all lancets fit all devices, so do your homework. Make sure that you can easily get replacement lancets to fit your device. Check the prices for replacement lancets as you compare devices.


Test Strips

Test strips are disposable strips that take a sample of blood. You insert a test strip into a meter to get a digital reading of your blood glucose level. Test strips are made to work with specific meters, so you’ll need to buy the appropriate brand and type.

Here are some things to consider when purchasing a meter and test strips. Some test strips are designed with a curve to help patients guide their fingers more easily to the application site. Other test strips are extra large to make them easier to handle. The packaging of the test strips may also be an important consideration for you. Some come packaged in a vial, whereas others are individually wrapped in foil. The foil wrappings can be more portable, but also more difficult to open. Some meters take a testing “disc” (containing enough room for multiple blood samples) or a drum with preloaded strips.

You’ll want to research the price of test strips as you consider which blood glucose meter to purchase (see more on this topic below). Test strips usually come in boxes of 50 or 100, and you can buy them online or in stores. The box of test strips will have an expiration date, and individually packaged strips usually last about 2 years. In the past, the U.S. Food and Drug Administration uncovered schemes to distribute counterfeit test strips. Always buy your strips from a reputable retailer, and check the FDA website (www.fda.gov) for updates on test strips or call the manufacturer if you have any concerns.

Sometimes, in rare cases, people who take certain medications containing sugars that aren’t glucose or who are undergoing medical procedures may receive false high readings with certain strips. Be sure to discuss your strips with your health care provider if you are put on a new medication or if there is a change in your health status.

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Generic Test Strips

You can also buy generic brands of test strips that are manufactured to work with specific meters. Make sure that the generic brand lists your meter on the packaging or in the product information.


Test Strip Storage

Test strips should be stored in their covered container and kept in a dry area. Not keeping your strips safe and dry could affect their accuracy. For example, keeping strips in the bathroom with the container uncovered may result in false blood glucose readings.


Blood Glucose Meters

If your doctor has told you that you need to frequently self-check your blood glucose, then a blood glucose meter is an essential tool for taking care of your diabetes. Only by keeping close tabs on your blood glucose levels and recognizing when they are out of range can you take steps to remedy the situation.

The meter measures an electric current in the blood that depends on the amount of glucose present. A sample of blood is placed on a small area of a test strip or disk. A special enzyme transfers electrons from glucose to a chemical in the strip, and the meter measures this flow of electrons as current. The amount of current depends on how much glucose is in the blood. This weak current flows through the strip and is measured in the meter. The meter produces an electronic reading of blood glucose levels in milligrams per deciliter (mg/dl).

There are also several meters that check more than blood glucose. One meter measures blood glucose and ketones (a byproduct that can indicate a serious medication problem). Another meter measures blood glucose, ketones, and lipids (including HDL and LDL cholesterol and triglycerides).


Plasma Versus Whole Blood

Meters measure the amount of glucose in whole blood, which is the complete composition of the blood flowing through the body. More simply, whole blood is the blood that is directly drawn from the body without further treatment. Several blood-glucose testing methods, however, measure the glucose contained in blood plasma. Plasma is a yellow liquid component of whole blood that has to be separated from blood using laboratory methods. The issue is that tests yield different blood glucose results when performed on whole blood versus blood plasma. Plasma test results tend to be 10–15% higher than results from whole blood.

Even though they measure the glucose levels in whole blood, today’s meters are adjusted to provide results in the plasma glucose equivalent, so blood glucose test results are consistent among all testing measures.


The sheer number of blood glucose meters on the market can be overwhelming. But the good news is that consumers now have more choices than ever in finding a device that fits their budget and lifestyle. Considerations for a blood glucose meter break down into roughly three categories: cost, performance, and your lifestyle. The following section will explore each category in detail.

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Considerations for Buying a Blood Glucose Meter

• Cost: Insurance coverage, price of test strips

• Performance: Accuracy, batteries, and meter replacement

• Lifestyle: Meter size, your vision and language, test site, user-friendliness, meter memory, and data management system

Cost Considerations

The cost of your blood glucose meter should be a consideration as you research different brands. Your health insurance may cover the cost of a meter and maybe the test strips. Meters are usually deeply discounted by the manufacturer through rebates and coupons, but you’ll want to analyze the long-term costs of any meter and the strips before you purchase it.

Insurance Coverage

Check with your insurance plan or company health program before you invest in a meter. For example, Medicare covers the cost of meters, strips, and lancets. Your insurance may pay for only specific meters or have a cost allowance. Also find out if you are covered for the test strips and how many you are allowed per year. Your insurance may cover more of the cost of meters and strips through a mail-order program. However, you will need to get a prescription to be reimbursed.

Price of Test Strips

In the long run, your meter’s test strips will cost you much more than the meter itself. You may be surprised by the cost when you go to buy replacement strips for your meter. The meter that seemed like a bargain at the time of purchase may turn into a major expense when it comes time to pay for strips (especially if you don’t get reimbursed for them by your insurance). Make sure you check the cost of the strips your meter uses before you buy it. Check Diabetes Forecast’s Consumer Guide and ads for lists of companies that sell discounted strips.

Performance Considerations

The U.S. Food and Drug Administration (FDA) regulates all meters made and distributed in the United States. Manufacturers are required to list devices with the FDA, as well as follow guidelines for marketing, labeling, safety, and efficacy. However, you—as the primary user—will be responsible for checking the performance of your meter over time.

Accuracy

Some machines require that you code each new batch of test strips with your meter in order to maintain accuracy (some do not). Test strips can vary from batch to batch. There may be differences in the amount of chemical on the strips in each batch. So you must standardize (or code) your meter to make up for these small differences when you open a new batch of strips. If you don’t code, all your results with the new strips may read higher or lower than they really are. Instructions for coding are included in every new package of strips. Some meters automatically code themselves—you don’t have to do anything when you open a new batch of strips or the disk.

You’ll also want to check the accuracy of your meter from time to time. You can do this one of three ways: perform an electronic check, use a “control” solution or strip, or compare your meter with a laboratory meter.

Your meter should perform an electronic check every time you turn it on. It will give you an error code if something is wrong. You can check the owner’s manual for instructions for correcting errors.

Meters often provide a standard solution, known as a “control” solution. This solution contains a known amount of glucose to help check for accuracy. Other meters use a control strip to check for accuracy. If you measure the amount of glucose in this standard solution or strip in your meter and your meter shows a reading that is too high or too low, your machine may be giving you a faulty reading. The manufacturer’s instructions will tell you how often to check with the control solution or strip for the best accuracy.


Write the date on your control solution when you open it and remember that it is usually good for one to three months, depending on the manufacturer.


If you are having a problem with accuracy, first check to see if your problems are being caused by old or damaged test strips. Then call the manufacturer of your meter. There may be something wrong with your meter. You can usually order a vial of standard glucose solution by calling your meter’s manufacturer.

In some cases, your health care provider can help you check the accuracy of your meter by using a laboratory meter in his or her office. Your health care provider might ask you to perform a blood glucose test just as you would on your own. Then, he or she might check your blood glucose using the laboratory machine. If the two results match, your meter is probably accurate.


Other factors can affect the accuracy of your meter. Altitude, temperature, and humidity can have unpredictable effects on glucose results.


In some cases, you, not the meter, may be giving inaccurate results. Researchers have found that practice, at least in the area of blood glucose monitoring, does not make perfect. Fresh from training by a diabetes educator, people start off getting accurate results. But as time goes by, people begin to get sloppy. Accuracy usually decreases over time.

Take your meter with you for checkups, and ask your health care provider to observe your technique from time to time. Or measure your blood glucose level with your own meter when your blood is drawn for laboratory glucose tests. Record your results. The two readings are best compared when you are fasting. When your lab-tested blood results are available, compare the numbers.

Comparing Home and Lab Results

• Make sure that you are comparing plasma blood readings (not whole blood) from your meter to your lab results.

• If your result was off by more than 5–10%, go over your technique with your diabetes educator or provider. If he or she can’t find any problems with your technique, it’s time to consider whether something may be wrong with your meter.

Monitoring: Problem Areas to Watch

• Your blood. Are you getting enough blood on the test strip? To increase blood flow, wash your hands in warm water, hang your hand down, and massage your hand from your palm out to your fingertip before pricking. You may find it less painful to prick the side of your finger rather than the fleshy pad. For some strips, once the drop is on the strip, you can’t add more blood. Washing your hands will also help prevent any perfumes or food residue from affecting your test results.

• Test strips. Are your strips fresh? Be aware of the expiration date. Avoid exposing the strips to light and moisture. Are you coding your meter to each new batch of test strips? Variations occur from one batch to another, even when made by the same manufacturer.

• Your meter. Check your meter regularly with the control solution specified by the meter’s manufacturer. Look in the instructions that came with the meter if you’ve forgotten the technique. If your meter can be cleaned, do it periodically. You may find a buildup of blood, dust, and lint that can affect the readings.

Batteries and Meter Replacement

Meters run on batteries, but each model handles batteries differently. Find out what kind of battery your meter takes before purchasing it. Consider the cost and ease of replacing the batteries.

Some models allow you to buy the battery and insert it into the meter yourself. These batteries might be specific to the meter and therefore could be more expensive and difficult to find. Or these batteries might be standard batteries (such as AA or AAA) that run in devices like flashlights or remote controls and therefore are cheaper and easier to find. Still other meters have no replacement batteries.

Most manufacturers will tell you how long the meter’s batteries will last. Some meters tell you when the battery needs replacing. Some companies will replace batteries for you, and others simply replace the whole meter.


With daily use, batteries generally have to be replaced every 1,000 readings.


Lifestyle Considerations

Your lifestyle is one of the most important considerations for choosing a blood glucose meter. With so many meters on the market today, you are bound to find a meter with at least a few of your preferred features.

Size

Some glucose meters are so small that they fit on a vial of strips, while others are larger, so people with big hands can handle them easily. Small meters are easy to slip into your pocket or purse. However, if you have trouble with small hand and finger movements, you may want to consider a larger meter. Larger meters may be heavier and clumsy to carry around. Some meters have rubber grips that make them easy to hold.

Your Vision and Language

Whether you have severe visual impairment or just have a hard time focusing on small print, you may want to consider this when choosing a meter. Some meters completely talk users through monitoring with both voice set-up commands and readings. The meter may also have buttons with raised imprints. Others have a large screen to make reading the numbers easy. If you have any degree of colorblindness, test a few different models. Make sure that you have no trouble reading the digital display.

Some meters display or speak in different languages, such as Spanish. Others use symbols instead of words to display information.

Test Site

Alternative blood glucose monitoring, such as the upper arm, thigh, calf, and palm, is available with some meters. Make sure to check your meter for the availability of this feature before using alternate sites. Alternate sites will give you more options, but these sites may not be as consistently accurate as your fingertips. For example, readings from alternate sites may vary after eating, after taking insulin, or during low blood glucose periods.

User-Friendliness

Make sure your meter or monitoring system is easy to handle, especially if you have arthritis. Several features can make meters easier to use. Some models require a smaller-sized drop of blood. Ask how much blood is required for each model you might be considering. With some models, too little blood may give a faulty reading, and you may need to repeat the test. This can be inconvenient at best, but it could be a problem for people with poor circulation in their hands or those who must check their blood glucose in cold environments.

Other models may require more hands-on time than others. For example, stay away from devices that require too much time if you’re always in a hurry. Some meters can measure blood glucose just seconds after a drop of blood lands on the strip. These devices can be very useful when you test often or in work and social situations, where a few seconds here and there really make a difference. If you are always on the move, you may want to consider a meter and insulin pen combination.


Blood Contamination

Contamination can be a serious concern if you have an illness such as hepatitis or HIV infection. So, choose a system that will keep handling of blood samples to a minimum. Don’t share lancet devices or meters in which blood can contaminate the device. Always dispose of sharps properly.


Support System

If you are using a meter for the first time, consider one that offers a video that teaches you how to do the reading. A picture or visual image can make a seemingly complicated procedure crystal clear. Also make sure that the company has a 24-hour toll-free number to call for any questions about the meter. Sometimes a quick phone call clears up a simple problem. Also check that your health care team is familiar with the model you purchase and that supplies are easily available in your area or by mail order.

Meter Memory and Data Management System

Your meter can do much more than give you a blood glucose reading. It can also store and manage these readings and sometimes even make recommendations for food or insulin doses based on this information.

Some meters can store up to 3,000 glucose readings. A big memory can be helpful for people who carry their meters around with them during the day. Some models have one-button memory recall to review recent results.

Your meter’s data management system is also important to consider. Some models will help you upload the information to a web portal that only you and your health care provider can access. Some models come with software programs that you download to your computer to help you track and visualize your results. These programs can provide trend analysis, averages, graphs, printouts, and more. This can make it easier for you and your health care team to pinpoint any problem areas that might arise. You’ll read more about keeping records of your readings in the logbook section below.

Surprisingly, data management systems don’t cost too much more than regular meters. Before you buy a system, check to see if your health care team uses or recommends one system over another. Also call the manufacturer’s toll-free number, and ask them what you will be getting. They should answer any questions you may have.


Don’t buy a high-end blood glucose data management system unless you can afford the extra cost. Many people find that they can get along with a good logbook. This is especially true if you have type 2 diabetes and monitor less often.


How to Use a Blood Glucose Meter

Follow your meter manufacturer’s instructions for calibrating, setting date and time, and using control solutions. Check to make sure your strips are not outdated, and store them within the proper temperature limits. Strips can be ruined if they are kept outside the range of acceptable temperatures. If you have problems, there is a toll-free number on the back of the meter that you can call for help. Read the instructions for possible test sites.

Equipment

• Lancet

• Test strip

• Cotton ball or tissue

• Blood glucose meter

• Logbook

Instructions

1. Make sure your hands and skin are clean and dry. Soap or lotion on your skin can cause incorrect test results.

2. Puncture the skin where testing is to be done with the lancing device. If there is a problem with potential hypoglycemia, use your finger for testing.

3. Squeeze or milk out the amount of blood needed by the individual meter. With alternative sites, follow manufacturer’s instructions.

4. Follow instructions to see if blood needs to be dropped on the test strip or if the finger or other site should be held so the strip can absorb the blood.

5. Apply firm pressure with a cotton ball or tissue to the lanced site until bleeding stops.

6. Dispose of the lancet and test strip according to local waste disposal laws.

7. Record your test results in your logbook. See more about logbooks below.

Continuous Glucose Monitors

A continuous glucose monitor (CGM) is a small sensor inserted under the skin that measures the fluid between cells called interstitial fluid. This measure correlates to blood glucose. The monitor communicates wirelessly with a handheld device that displays your interstitial fluid level. The sensor must be changed every few days or so. The system can display real-time glucose levels at 1- and 5-minute intervals, and alarms can be set to alert patients of high or low glucose levels. Rapid rate of change can also be displayed. In addition, these systems come with data management software to help patients see readings in trend charts and graphs.

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CGMs are more expensive than traditional meters. However, some insurance is beginning to cover these devices.

Although CGMs have not been widely studied, some initial studies have shown that they may beneficial for patients who wear the devices all the time and are highly motivated. For example, continuous glucose monitoring along with tight blood glucose management can lower A1C in adults with type 1 diabetes. Children, teens, and younger adults may benefit, too.


Currently, the FDA requires users to confirm CGM readings with readings from a traditional blood glucose meter before making treatment decisions because CGM devices are so new.


Logbooks

One of the most important tools in your diabetes toolbox is also the most overlooked. A logbook may not look like much, but it will help you and your health care providers understand your blood glucose levels. It will alert you to any red flags that could signal a serious problem and help you determine whether your treatments are working—and how to fine-tune them.

Your health care provider can provide you with a logbook or your meter may come with one. Call the toll-free number for your meter manufacturer to request more. Some manufacturers have logbooks that you can download to your computer and print.

If you like the idea of keeping a paper logbook, you can photocopy blank pages and compile them in a loose-leaf notebook or create your own custom logbook. You may want a lot of room to write in your logbook. Consider buying a spiral-bound notebook or using a loose-leaf notebook, where you can add pages as needed, to jot down extra notes. You may find it useful to have extra space to record different symptoms and situations that could be relevant to your health. Your logbook is an important tool that can help you spot patterns in your blood glucose control, so be sure that it is easy to use.

Some meters come with an electronic logbook that records your readings and allows you to enter comments about your meals or other situations. Some people may prefer the convenience of using an electronic logbook rather than paper. However, you should always keep some type of logbook rather then just storing readings in your meter’s memory.

Ask your health care provider which readings you should write down in your logbook. You should also bring your logbook with you during doctor’s appointments so that you can look over your readings together.

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Ketone Tests

People with type 1 diabetes, and occasionally people with type 2 diabetes, can experience a dangerous condition called ketoacidosis. Ketoacidosis is a buildup of ketones in your urine. It can lead to a diabetic coma and death if left untreated. It can happen at any time, but may be more likely during illness, stress, or pregnancy. You can read more about ketoacidosis in chapter 8 about blood glucose emergencies.

Luckily, you can test the ketones in your urine with a urine test strip to make sure you don’t develop ketoacidosis. It’s important to detect ketones before they grow to large levels. Checking for urine ketones is especially important for people with type 1 diabetes who do not make any insulin. People with type 2 diabetes usually produce some insulin, so they are less likely to develop ketoacidosis. However, everyone with diabetes needs to know how and when to check for ketones. Read more about when and how to check for ketones in chapter 8.

Urine Ketone Test Strips

You put a test strip in your stream of urine or in a cup to test for ketones. Urine strips vary in how quickly they show a result, so read and follow the directions so you know how long to wait. A change in color will indicate the presence of ketones. Some strips will indicate ketone levels as 0, trace, moderate, or large, whereas others will give a specific reading. Some urine strips also measure glucose and have two test pads on each strip.

Where to Buy Supplies

People with diabetes now have more choices than ever about where to buy their diabetes supplies and devices. You can shop online, in a local or chain pharmacy, and through the mail. It’s up to you to decide which is the most convenient and cost-effective place to shop. Be wary of online marketplaces where people sell and auction personal items. It is not possible to know if testing supplies have been stored properly or have been altered in any way. Only buy from a reputable source.


Packaging

Individually foil-wrapped ketone strips are the most expensive up front, but they last longer. They may save you money because you are unlikely to need to test ketones very often. Ketone strips that come in a vial all spoil at the same time, probably 6 months after you open them.


Pharmacies

Some pharmacies offer a smaller selection of equipment, so check the aisles to see how your pharmacy stacks up. If you have a good relationship with your pharmacist, you may be able to ask him or her to order what you want. Although small pharmacies can be more expensive, establishing a good working relationship with your pharmacist can save you a lot of running around. Pharmacists can often give you information about the ins and outs of different products and models. Local pharmacists will know the products they sell and will be able to spend time training you to use the purchase. This is often a real, convenient advantage.


Most grocery store and chain pharmacies carry diabetes supplies, which might be convenient if you are shopping for other items.


Diabetes Supply Stores

Another shopping option is to visit a diabetes specialty store. To find one near you, call your local American Diabetes Association office or check in the phonebook under “Diabetes” or “Medical Supplies.” If you are lucky enough to have one nearby, you may be able to get many nonprescription items along with diabetes information and support in one easy stop. You may also find a selection of healthy foods, books, and information on local diabetes events and organizations. Many diabetes shops have knowledgeable staff who can help you compare models, answer questions, and provide training on new tools.

Mail Order

Purchasing your diabetes supplies, such as test strips, through a mail-order supplier can save you money. However, you’ll also have to calculate the extra time it will cost to ship supplies and perhaps the extra time to deal with insurance coverage.


Buying Supplies Online

When purchasing supplies online, make sure to look for an Internet site that is secure and reputable. The FDA recommends purchasing from websites that are located in the United States and provide clear ways to contact the company with questions or concerns.


Making Mail Order Work for You

• Pay extra attention to timing. Some orders will ship automatically, whereas others will take up to 2 weeks. Order your supplies far enough in advance that your current supply won’t run out before the new ones arrive.

• The mail-order company should confirm your insurance coverage before filling out your first order. If you use Medicare to help pay for supplies, note that the prices shown in advertisements or quoted over the phone may differ from the amount that Medicare will reimburse for that item.

• If you live in a warm climate or order during the summer, ask how perishable items will be shipped. Strips can spoil in excessive heat, so overnight shipping is best for these items.

• Compare prices by shopping around. Most mail-order firms have toll-free numbers and websites.

• Always keep copies of any orders you send through the mail. If you call in an order, be sure to write down when you placed the order and what you ordered.

• Check the expiration date on each item that arrives. If you’ll need the item in 6 months, make sure it doesn’t expire in 2 months. Send back all items with expiration dates that are just around the corner.



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