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False High Glucose Readings

6 Things That Can Affect Blood Glucose Readings

6 Things That Can Affect Blood Glucose Readings

Many of us rely on blood glucose testing to stay in control of our sugar levels. But meters can be funny things: there may be times when the readings they provide are inaccurate. Modern meters have made inaccurate readings less common, but it’s important to know that it can happen, and why. Bear these six factors in mind when you’re testing your blood. 1. Out of date test strips All test strips have an expiry date. Check the box to find out if your test strips are out of date. Out of date test strips should never be used. They often provide inaccurate results. Some test strips have to be used within a month of being opened. Check the box to see if this applies to your test strips. Test strips that aren’t properly looked after can also lead to an inaccurate reading. Strips should be kept at room temperature, in a cool dry place. They should also be kept in their original container, and not exposed to sunlight. 2. Extreme temperatures can affect blood glucose readings Extreme temperatures do funny things to blood glucose meters. If it’s a very cold day, try to test your blood sugar inside, where it’s a bit warmer. If it’s a very hot day, see if you can test in the shade if possible. Studies have found that cold meters tend to produce inaccurately low readings, and hot meters inaccurately high readings. Specific meters should state what their temperature ranges are. The FreeStyle Lite, for instance, has an operating temperature between 4 and 40 degrees and a storage temperature between -20 and 60 degrees. 3. Sugar, or other substances, on your fingers There’s a reason we’re advised to wash our hands before testing our blood. We’ve all heard stories of people testing with a smudge of sugar on their fingers and getting readings of well over 30, but it doesn Continue reading >>

Factors Affecting Blood Glucose Monitoring: Sources Of Errors In Measurement

Factors Affecting Blood Glucose Monitoring: Sources Of Errors In Measurement

Go to: Measuring Accuracy Accuracy of a blood glucose meter is a measure of how closely the average of a series of values reflects the reference value. As seen in Figure 1 (left), the average of a series of values can be perfectly accurate, although none of the individual values is representative of the reference. Precision describes the reproducibility of a series of values, independent of the closeness of any of the values to the reference. Again, as seen in Figure 1 (center), a series of values can be highly precise, although none of the individual values is representative of the reference. Only when a series of values is both accurate and precise (Figure 1, right) do the individual values actually reflect the reference value. Figure 2 shows these same definitions applied to SMBG. The green line defines perfect accuracy. As seen on the left, a series of measurements, half of which are high by 100 mg/dl and half low by 100 mg/dl, would be considered perfectly accurate as a set since the high values and the low values would average to the true value. Conversely, as seen in the center of Figure 2, a series of measurements, each of which is high by 100 mg/dl, would be considered perfectly precise although biased. As seen on the right in Figure 2, only when a series of values are both accurate and precise do all of the values fall exactly on the green line of accuracy. The best single measure of both accuracy and precision is the mean absolute relative error (MARE) (also called mean absolute relative deviation or MARD and mean absolute error or MAE). Mean absolute relative error is calculated by taking the average for the set of individual absolute errors relative to its reference value (Figure 3). So, for example, with a reference value of 100 mg/dl, measured values of b Continue reading >>

5 Things That Can Affect Blood Glucose Readings

5 Things That Can Affect Blood Glucose Readings

People with diabetes often have to test their blood sugar levels up to multiple times per day, but blood glucose meters can sometimes display inaccurate readings. At the time, you may not realise that readings could be wrong. This could then affect your treatment regimen and potentially cause you problems, especially if you inject insulin when your blood glucose meter displays an erroneous high reading. Of course, modern meters have evolved so inaccurate readings are much less common, but it is still important to be aware of why false readings can occur. Here are five factors to bear in mind when testing your blood sugar. 1. Sugary substances on your fingers Even the slightest bit of sugar on your fingers can ramp up your test result. But this also goes for bits of dirt and traces of other food that may still be on your fingertips. Make sure you wash your hands before each test to ensure the most accurate result. 2. Wet fingers Once you’ve washed your hands, make sure they are thoroughly dry before testing. If a blood drop becomes mixed with water it can dilute the sample, causing an inaccurate reading. 3. Expired test strips All test strips have an expiry date. If you use a test strip which is out of date then it can lead to faulty results. Make sure you know the expiration date of your strips. If your test strip is out of date, do not use it, as the result cannot be trusted. 4. Extreme temperatures Extreme temperatures can have a big impact on blood glucose meters. Meters should state their specific temperature ranges, and testing outside of this range can affect test results. If a meter is too cold it tends to produce inaccurately low readings, and hot meters inaccurately high readings. If it’s a very cold day, test your blood indoors, where it’s warmer. If it Continue reading >>

Little Things That Can Have A Big Impact On Your Blood Glucose Reading

Little Things That Can Have A Big Impact On Your Blood Glucose Reading

When you have diabetes, it's vital to make sure you're getting the most accurate reading when checking your blood glucose levels to ensure tight diabetes control. Emmy Suhl, M.S., R.D., C.D.E., at Joslin Diabetes Center, reviews different things that can impact your blood glucose reading and how to avoid them. Things that Can Affect your Blood Glucose Reading A dirty meter. Outdated test strips. If test strips are not compatible with the meter you're using, results may be inaccurate or no result will be obtained. If the wrong strip is used, it may not even fit into the slot or it may fit, but the meter won’t turn on, Suhl says. Substances left on your hands. For example, if there is a sugary substance on the finger used for lancing, even if it’s a small amount that can’t be seen, a high blood glucose reading can result. Temperature changes (heat/humidity/cold air). Not a big enough blood sample on the test strip. Wet fingers. Fluid mixes with blood and can cause an inaccurate reading. How to Avoid an Inaccurate Blood Glucose Reading Before using the meter for the first time and then again every few weeks, check your meter using the control solution, Suhl says. Control solution is only good for three months once opened. Label the control solution bottle with the date you open it. Check the date and shake control solution before using. The value the control solution gives should be in the target range printed on the strips container. Make sure strips are not expired. Check the date on the strip container. Make sure code on strip container matches the code on the meter. Wash hands in warm water and dry them off after. Massage hands before checking. Select site on one side of the center of a fingertip. Rotate sites for each check. Apply gentle pressure to lanced finge Continue reading >>

Getting Accurate Blood Glucose Test Results

Getting Accurate Blood Glucose Test Results

For the most part, blood glucose meters—devices that measure and display blood glucose levels—are simple to use and provide readings you can trust. But they aren't perfect and inaccurate readings are possible. Extremely high or low readings that are made in error can have serious consquences. Inaccurate readings happen for a variety of reasons, including human error. But the error can usually be corrected without much effort. Here are some common mistakes users make along with tips to help you improve the reliability of your device and your test results. But first, it's important to note that if you get a reading that seems way off—especially one that doesn't match your symptoms—always perform a re-test. When re-testing, take your time to ensure you are using the strips and the device correctly and repeat the procedure. If you get a similar reading again, call your healthcare professional or the phone number on the back of the meter as malfunctions can occur and product recalls happen periodically. The following factors can impact meter accuracy.If you find you are contributing unintentionally to the problem, take the necessary steps to get the right results: Be sure your meter and hands are clean. It seems like a no-brainer, but a dirty meter can alter your reading. Clean your meter regularly, and before you do a reading, wipe off any noticeable blood, dirt, or grease. It's also vital to perform your test on a clean fingertip. Wash your hands with soap and warm water before extracting a blood sample. Be aware of test strip issues. Make sure your test strips are compatible with your meter. Saving money by purchasing less expensive strips that are not designed to work with your meter is a bad idea. Be sure the strip is inserted correctly into the meter. Test stri Continue reading >>

What Are The Causes Of High Glucose Blood Test Results?

What Are The Causes Of High Glucose Blood Test Results?

High blood glucose may be the signal of a developing medical condition or may simply be a short-term response to recent eating or stress. Diabetes, including gestational diabetes associated with pregnancy, is a prevalent cause of high blood glucose test results. High blood glucose levels can also indicate thyroid disease or pancreatic inflammation. Certain medications can cause your blood glucose levels to spike as well. Video of the Day If you forget to fast prior to a fasting blood glucose test, high glucose levels may be caused by the normal rise in blood sugar that occurs after eating. If you are given a blood glucose test after eating, be sure to alert your physician, who may suggest a follow-up test to ensure proper testing conditions. High blood glucose levels are the hallmark of type 1 and 2 diabetes. They occur in the early stages of these conditions, before other symptoms appear. Diabetes specific to pregnancy, or gestational diabetes, also causes an increase in blood sugar levels. To best diagnose prediabetes or diabetes, your doctor will likely order follow-up glucose tests on different days. She may also recommend an oral glucose tolerance test, in which your blood glucose levels are measured before and after consuming a sugar-containing drink. You will also likely undergo a hemoglobin A1c test, which serves to measure your average blood sugar levels over the past few months. Apart from diabetes, a large number of less common medical conditions can also cause high blood glucose levels. Such conditions include an overactive thyroid gland, pancreatic inflammation and certain cancers. Higher-than-normal blood sugar levels may also be caused by infections, especially if they are severe. Certain medications, notably corticosteroids, can raise blood glucose level Continue reading >>

Blood Glucose Monitors: What Factors Affect Accuracy?

Blood Glucose Monitors: What Factors Affect Accuracy?

Sometimes my blood glucose monitor seems to give incorrect readings. What can I do to make sure the measurement is accurate? Answers from M. Regina Castro, M.D. When used correctly, blood glucose monitors — small devices that measure and display your blood sugar level — are usually accurate. But occasionally they may be incorrect. Consider these factors that affect meter accuracy and the steps to resolve or prevent the problem: Factors that affect accuracy Solutions Test strip problems Throw out damaged or outdated test strips. Store strips in their sealed container; keep them away from heat, moisture and humidity. Be sure the strips are meant for your specific glucose meter. Extreme temperatures Keep your glucose meter and test strips at room temperature. Alcohol, dirt or other substances on your skin Wash and dry your hands and the testing site thoroughly before pricking your skin. Improper coding Some meters must be coded to each container of test strips. Be sure the code number in the device matches the code number on the test strip container. Monitor problems Fully insert the test strip into the monitor. Replace the monitor batteries as needed. Not enough blood applied to the test strip Touch a generous drop of blood to the test strip. Don't add more blood to the test strip after the first drop is applied. Testing site location If you're using a site other than your fingertip and you think the reading is wrong, test again using blood from a fingertip. Blood samples from alternate sites aren't as accurate as fingertip samples when your blood sugar level is rising or falling quickly. The amount of red blood cells in your blood If you are dehydrated or your red blood cell count is low (anemia), your test results may be less accurate. Blood glucose monitor quality Continue reading >>

Interferences And Limitations In Blood Glucose Self-testing

Interferences And Limitations In Blood Glucose Self-testing

Interferences and Limitations in Blood Glucose Self-Testing 2Institut fr Diabetes-Technologie Forschungs- und Entwicklungsgesellschaft mbH, Ulm, Germany 3Roche Diabetes Care GmbH, Mannheim, Germany 4Research Institute of the Diabetes Academy Mergentheim (FIDAM), Bad Mergentheim, Germany 5Diabetes Clinic for Children and Adolescents, Muenster, Germany 7Forschergruppe Diabetes e.V., Munich-Neuherberg, Germany Oliver Schnell, MD, Forschergruppe Diabetes e.V., Ingolstaedter Landstrasse 1, 85764 Munich-Neuherberg, Germany. Email: [email protected] Copyright 2016 Diabetes Technology Society This article has been cited by other articles in PMC. In general, patients with diabetes performing self-monitoring of blood glucose (SMBG) can strongly rely on the accuracy of measurement results. However, various factors such as application errors, extreme environmental conditions, extreme hematocrit values, or medication interferences may potentially falsify blood glucose readings. Incorrect blood glucose readings may lead to treatment errors, for example, incorrect insulin dosing. Therefore, the diabetes team as well as the patients should be well informed about limitations in blood glucose testing. The aim of this publication is to review the current knowledge on limitations and interferences in blood glucose testing with the perspective of their clinical relevance. Keywords: blood glucose testing, diabetes, interference, reliability, self-monitoring of blood glucose, SMBG Self-monitoring of blood glucose (SMBG) both in insulin-treated and non-insulin-treated people with diabetes is supported by recently published trials, reviews, meta-analyses, and guidelines. 1 - 7 SMBG is recommended to be performed in a structured approach. 2 , 5 , 8 , 9 It is reported to be only Continue reading >>

Help Your Patients Get Accurate Blood Glucose Readings

Help Your Patients Get Accurate Blood Glucose Readings

With over 20 million patients with diabetes in the United States, many of these patients must rely on monitoring their blood glucose at home to ensure that they are staying within their target goals. Unfortunately, too often patients receive inaccurate glucose readings due to a variety of factors. This article will focus on some common causes of inaccuracies with glucometer results, including environmental factors, hematocrit issues, sampling errors, and testing interferences. Environmental Factors Test strips that are stored in vials, as opposed to strips that are individually wrapped in foil, are susceptible to the effects of oxygen and moisture. Several small studies that reviewed the effects of glucose test strips left open in their vial for times ranging from 2 to 18 hours showed variances in blood sugar results from 9% higher to 60% lower than the actual results. A study in Diabetes by Lilavivat et al, in 2002, reported varying results for one patient between 94 and 307 mg/dL over the course of a few weeks. It was determined that the patient's test strips had been exposed to moisture. These factors must not be overlooked, given that many patients will keep their testing supplies in a bathroom or kitchen environment. Make sure that your patients understand to always keep their test strip vial closed when not in use. Heat exposure can also be a factor for vials of test strips as well as the individually foil-wrapped test strips. This is particularly a consideration for patients who use mail order as well as patients living in warmer, humid climates who may not use a source of air conditioning in their home. Counsel patients to make sure that they do not leave their test strips in the mailing box for extended periods of time if they order by mail and to use insulated Continue reading >>

An Important Step For Accurate Glucose Readings

An Important Step For Accurate Glucose Readings

Blood glucose monitoring is an important part of managing diabetes, but according to a new study in the journal Diabetes Care, failure to take the simple action of washing your hands with water before pricking your finger could result in falsely elevated readings. Cleaning the finger with an alcohol swab prior to taking a blood sample is commonly recommended as a way to make sure the test site is clean. To determine whether alcohol swabbing effectively removes fruit residue, researchers at the Juntendo University Graduate School of Medicine in Tokyo measured the blood glucose levels of 10 volunteers without diabetes under a variety of conditions. As a control, the participants’ fingers were cleaned and a fingerprick check was conducted to determine their true blood glucose levels. The volunteers then peeled either oranges, grapes, or kiwis, and then had their blood glucose checked immediately, after swabbing with alcohol, and again after washing with tap water. The researchers found that when the volunteers’ hands were cleaned with tap water, their blood glucose readings matched their readings prior to peeling the fruit, generally around 90 mg/dl. However, when their glucose levels were measured immediately after peeling the fruit, on average their readings shot up to 170 mg/dl after peeling an orange, 180 mg/dl after peeling a kiwi, and 360 mg/dl after peeling a grape, respectively. And even when they had swabbed their fingers with alcohol — in some cases as many as five times — prior to the measurement being taken, the readings still remained elevated over their actual blood glucose level. In an interview with Reuters, Robert Cohen, MD, an endocrinologist who was not involved in the research, noted that “People are used to pricking the finger, drawing a bloo Continue reading >>

6 Factors That Can Affect Blood Sugar Readings

6 Factors That Can Affect Blood Sugar Readings

6 Factors That Can Affect Blood Sugar Readings 6 Factors That Can Affect Blood Sugar Readings When testing your blood sugar, there are a host of issues that can affect the accuracy of the results. This is not only frustrating but also dangerousyou want to make sure youre giving yourself the right amount of insulin to regulate your blood sugar if youre taking insulin, and you want to make sure you know your real numbers to work with your doctor to control your blood sugar and avoid complications. Avoid these six common problems before you prick that finger: You may not be getting a big enough sample of blood on the test strip to precisely measure your blood sugar. You also may be using the same finger for every test . And there are other commonly performed missteps in testing. User error is a large contributor to inaccurate readings, so talk to your endocrinologist or CDE about how to properly perform all the steps involved in testing. Are your fingers a little sticky from just-eaten food? If you ate an orange and left residue on your fingers, your meter will add the high sugar content from the citrus to your blood sugar measurement, resulting in a much higher number than you actually have. Leftover food, lotion, or fluid (including water) on your hands can cause wrong readings. Wash your hands with warm water and soap (dont lick them or use rubbing alcohol), and thoroughly dry them before testing. Believe it or not, your surroundings can also affect your blood sugar readings. The altitude, humidity, and room temperature of your environment can affect either your body or the strips you use, or both. Some meters come with instructions on how to get accurate results when in extreme environments. If your meter doesnt include this information, ask your diabetes doctor about Continue reading >>

Acetaminophen Can Affect Meter And Cgm Readings

Acetaminophen Can Affect Meter And Cgm Readings

The common pain-relief drug does not affect actual glucose concentration in the bloodstream, however. There’s been evidence as far back as 2009 that acetaminophen can cause inaccurate blood sugar readings with meters. Now, a more recent study suggests that the common pain reliever also might interfere with continuous glucose monitor (CGM) readings, as well. In July 2009, The Journal of Diabetes Science and Technology published a paper discussing sources of meter errors in measurement of blood glucose levels, including patient use of acetaminophen. Acetaminophen is a mild painkiller and fever reducer that people use as an alternative to aspirin; although it’s been hard for scientists to pin down exactly how acetaminophen works, the drug is believed to moderate the body’s production of prostaglandins, a hormone-like lipid which, among other things, helps regulate sensitivity to pain. Researchers in the 2009 study documented how acetaminophen use seemed to cause errors in blood glucose readings with meters. The paper has found no chemical or metabolic link between acetaminophen and the body’s production of, or sensitivity to, glucose or insulin. The researchers did say older meters were more prone to these erroneous readings than newer meters, but that such fluctuations can be possible with all meters they researched. Now, a similar inaccuracy has been documented in connection with CGM use. In 2015, clinical investigators published a paper in Diabetes Care describing meter and monitor variations for a group of acetaminophen-using patients who tested both with meters and CGMs. The study, led by Dr. David M. Maahs of the University of Colorado Barbara Davis Center for Childhood Diabetes, was a stress test to predict the reliability of investigational closed-loop arti Continue reading >>

Be Aware Of False Glucose Results With Point-of-care Testing

Be Aware Of False Glucose Results With Point-of-care Testing

Be Aware of False Glucose Results With Point-of-Care Testing Point-of-care blood glucose monitoring systems are known to provide an accurate, timely, and cost-effective means for determining blood glucose levels in diabetic patients.[ 1 ] In fact, these devices have become a mainstay for blood glucose monitoring in both hospitals and outpatient settings. In many cases, this has allowed patients to achieve better glycemic control and avert the negative health outcomes associated with hypoglycemia or hyperglycemia. However, patients and practitioners may not know that the administration of certain substances can result in erroneously high values when using glucose meters. One situation was recently reported. An elderly immune-compromised patient was admitted to a hospital ICU with sepsis. He was started on intravenous immunoglobulin treatment with OCTAGAM (immune globulin intravenous [human] 5% solvent/detergent treated). The hospital routinely stocked another manufacturer's immunoglobulin preparation but recently switched to Octagam. The manufacturer of Octagam has added maltose (100 mg/mL) to make it isotonic with plasma, but this substance can also interfere with certain blood and urine glucose tests. The ICU staff were unaware that maltose could cause falsely elevated glucose values in glucose meters that use the glucose dehydrogenase method for testing (see table 1 ). The package inserts for glucose dehydrogenase test strips and Octagam describe this problem, but the information was overlooked. To test the patient's blood, nurses were using an Accu-Chek system and Accu-Chek Comfort Curve test strips, which use the glucose dehydrogenase method for determining glucose levels. Thus, the Accu-Chek provided falsely elevated glucose values, which were used to adjust the p Continue reading >>

Are Those Glucometer Results Accurate?

Are Those Glucometer Results Accurate?

Patient and environmental factors Both patient and environmental factors can interfere with obtaining accurate glucometer results. These include sampling errors, improper storage of test strips, inadequate amount of blood applied to the test strip, improper meter coding, and altitude.1 Temperature extremes and humidity can denature, inactivate, or prematurely rehydrate enzymes and proteins within the test strip.1 GO meters can overestimate glucose levels at low temperatures, while GDH meters can produce unpredictable results in increased humidity.1 The detector portion of the meter is composed of electronics and should be protected from temperature extremes and excessive moisture as well.1 In high altitude, both GO and GDH meters can produce unreliable results, with a tendency to overestimate blood glucose levels.8 Another variable confounding the accuracy of glucometer readings at high altitude is the potential for secondary polycythemia, which can result in underestimation of glucose levels.8,9 Physiologic factors Physiologic factors that can cause inaccurate glucometer results include hypoxia, abnormal pH, hyperuricemia, jaundice, polycythemia, anemia, peripheral vascular disease, and hypotension resulting in poor perfusion.1,7,9 Elevated oxygen tension in patients receiving oxygen therapy can falsely lower glucometer results for GO meters, while hypoxia can falsely elevate glucose results for these meters.1,3 Low pH (< 6.95), such as in diabetic ketoacidosis, falsely lowers glucose readings in GO meters, while a high pH falsely elevates glucose readings.1,10 Elevated serum uric acid (> 10-16 mg/dL) and elevated total bilirubin concentration (> 20 mg/dL) can cause overestimation of blood glucose levels due to electrochemical interaction at the electrode site in GDH-P Continue reading >>

10 Surprising Causes Of Blood Sugar Swings You Probably Didn’t Know

10 Surprising Causes Of Blood Sugar Swings You Probably Didn’t Know

1 / 11 What Causes Blood Sugar to Rise and Fall? Whether you were recently diagnosed with type 2 diabetes or have been living with the disease for several years, you know how fickle blood sugar levels can be, and how important it is that they stay controlled. Proper blood sugar control is key for helping ward off potential diabetes complications, such as kidney disease, nerve damage, vision problems, stroke, and heart disease, according to the National Institutes of Health (NIH). If you keep your levels in check on a daily basis, it will help you stay energized, focused, and in a good mood. You’ll know if your diabetes is poorly controlled if you experience symptoms such as frequent urination, sores that won’t heal, blurred vision, and unexplained weight loss. According to the American Diabetes Association (ADA), proper medication, effective meal planning, regular exercise, and use of a blood glucose meter to track your numbers routinely can all help you keep your levels within a healthy range. The ADA recommends blood glucose be 80 to 130 milligrams per deciliter (mg/dL) before meals, and below 180 mg/dL two hours after the start of a meal. Furthermore, the organization recommends getting an A1C test, which measures your average blood glucose over the past two to three months, at least twice per year if your levels are stable and you are meeting treatment goals. Learning how different habits can cause your blood sugar to fluctuate can help you better predict how your levels will swing. You may be more likely to experience hypoglycemia, or low blood sugar if you have advanced-stage diabetes, according to the ADA. Meanwhile, high blood sugar, or hyperglycemia, may be caused by factors such as not using enough insulin or other diabetes medication, not following a prop Continue reading >>

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