The Healing Handbook for Persons with Diabetes
Chapter 5: Monitoring
Self-monitoring blood glucose (SMBG) and urine testing are guides to diabetes control. Urine testing is an indirect method for measuring blood sugar. SMBG is a more direct method of monitoring your blood glucose level. Your diabetes educator or doctor my prescribe SMBG urine testing. Most health-care professionals prefer SMBG because of the following limitations of urine testing:
- You cannot test for low blood sugar (hypoglycemia) with urine testing.
- Sugar shows up in urine only when the blood glucose level exceeds the kidney threshold, and this threshold could be high.
- Because urine collects in the bladder over time, urine testing provides general information on blood glucose level over a few hours, rather than exact information on the level at test time.
- SMBG allows you to determine the pattern of blood glucose levels and make necessary changes in your diet and exercise program or insulin dose.
- With SMBG, you can measure precisely the effects of changes in exercise, diet, and insulin on your blood glucose level.
- SMBG helps you avoid insulin reactions.
- The precise, immediate information provided by SMBG allows you to respond quickly to an elevation or decline in blood sugar.
- During an illness, the accurate information provided by SMBG can serve as a basis for treatment.
Self Monitoring Blood Glucose
If your diabetes educator or doctor recommends SMBG, he or she will prescribe a testing schedule of 1 to 4 times a day. You may be asked to test at various times.
- Before meals
- 2 hours after a meal
- At bedtime
- At 3 a.m.
- Before an insulin reaction
- Anytime you sense that your blood glucose level is high
- More frequently on sick days
You may need fewer tests once you have established your blood glucose patterns.
Your SMBG test times: ______________________________________
Remember, SMBG results are your guide to good control.
- Lancet Device
- Test Strips
- Alcohol Wipes
- Log Book
- Optional equipment: a computer and software for analyzing results that are stored in the memory of most new meters.
SMBG instructions vary, depending on the meter or sensor you use. Make sure you carefully follow the instructions for your device.
All SMBG tests require a drop of blood. The side of the tip of the middle or ring finger is usually the most convenient and least painful place to obtain blood, but you can use any finger, or even an earlobe. Using the same finger (or pair of fingers) causes a callus to build up. You'll feel less discomfort but still obtain enough blood for each test.
Here are the steps for obtaining a drop of your blood:
- Wash your hands with soap and warm water and dry them completely
Clean the area with alcohol and dry completely.
- Prick the finger tip with a small, pronged lancet. A spring lancet device gives a quick puncture with less discomfort.
- Hold your hand down, and milk the finger from the palm towards the tip. If little blood appears, wait a couple seconds and milk again. Do not squeeze close to the puncture.
- Turn your hand palm down, so that the drop hangs.
- Catch the drop of blood on the special test strip pad or designated area.
- Follow the instructions included with your SMBG sensor or meter, and instructions from your diabetes educator, for measuring blood glucose.
- Record your test result.
Your personal goal depends on your age, type of diabetes and how long you've had it, other health conditions, life style, and desire for control. Here are some guidelines:
|Before a Meal
|After a Meal
Your diabetes educator and physician will help you set your own goals. For some people, a blood sugar level below 80 mg is too low, while for others a level under 100 mg is too low. A level over 120 before a meal is too high for some, while for others it is normal.
Keeping a record of SMBG test results is vital. You and your health-care professionals use this information to make safe adjustments to your diet, exercise plan, and insulin or oral hypoglycemic pills. Make sure your SMBG test record includes any unusual events, such as illness, stress, and changes in exercise or activity level.
Meters and sensors for testing your blood glucose level vary in size, weight, test timing, range, and calibration method. They can read blood sugars as low as 0 and as high as 600 mg. Results may be obtained in 20 seconds to 2 minutes. Some tests require blotting or wiping, while others do not. All the available meters and sensors have been tested for accuracy. costs vary from $50 to $150. Insurance may pay 80% of the cost for people with insulin dependent diabetes. Trade-in offers and rebates can help reduce costs. At this time, all meters require test strips, which cost $.65 to $.80 each and are not covered by most insurance plans.
Photometric (color reflectance) meters have been around the longest and have proven reliable and accurate. They use a light source with filters and a lens to detect the color change on a strip pad caused by glucose in the blood. A digital result is produced. Photometric meters include the Accu-Chek, One-Touch, Tracer, Diascan and Glucometer.
An alternative technology for glucose measurement uses electrochemical detection. Glucose in the blood causes a reaction on the test strip that produces a tiny current. The meter detects the current and reports a digital test result. The Exactech Companion uses this technology.
Some people prefer to see the lancet stick their fingers, while others prefer a hidden lancet. Button activated, pen-shaped devices are easy to use. Reliable lancets like the Softouch, Glucolet, Penlet, and B-D Autolance are available for $15 to $20.
NOTE: Diabetes Forecast magazine publishes its Yearly Consumer Issue and Buyer's Guide in October. In this issue, you'll find information on available meters and sensors, including prices and accuracy evaluations.
Glycosylated hemoglobin, or Hgb AlC, is a test that reflects the average of your blood sugar levels over the past 2-3 months. Hemoglobin is a protein found inside red blood cells. Glucose binds to hemoglobin, causing it to become glycosylated. The higher the percentage of hemoglobin that is glycosylated, the higher your average blood sugar for the past 2-3 months.
In these examples, the circles represent red blood cells, the large H inside the circles represent hemoglobin, and the small G's represent glucose. Where a G is present in a cell, the hemoglobin is glycosylated.
If you have Type I diabetes, your diabetes educator or doctor may instruct you to test your urine for ketones when your blood sugar is over 200 mg, even if you use SMBG to monitor your blood glucose control. This is because SMBG dopes not alert you to presence of ketones.
Remember that when there is not enough insulin present to funnel glucose into your cells, your body tries to use stored fat to make fuel available to your cells. Fat in fat cells is broken down to "fatty acids," which pass through the liver and form ketones (acetone). Ketones are exhaled and excreted in urine.
Ketones in your urine is a warning sign of a low insulin level that requires quick action. If your urine tests positive for ketones and your blood sugar is high, contact your doctor or diabetes educator immediately, or, if instructed, use Sick Day Management guidelines (see Chapter 10). The only exceptions are when you have ketones following an insulin reaction or if your blood glucose level is near normal.
You can test for ketones with Ketostix, Chemstrip UK, or Acetest tablets. Shop around for the best prices. And be sure to follow the package instructions.
Urine testing is easy, painless, and inexpensive. For SMBG, you need to invest up to $120 in a meter/sensor and also buy test strips at 65 to 80 cents each. Not all insurance policies cover strips, this can get expensive for people on fixed incomes. And some people just can't learn to draw a drop of blood. So diabetes educators and doctors may decide that urine testing is the best option for some patients.
- Urine testing is simple and inexpensive, and it may be an adequate means of measuring blood sugar for some people. If your diabetes educator or doctor prescribes urine testing, he or she will recommend a testing schedule.
Your Urine test times: _____________________________________
- Urine test strips or tapes are easy to use -- just dip and read. Test timing is specific, however. Be sure to read the directions that come with your urine test, and review these instructions with your diabetes educator to make sure you understand them. Available urine tests include TesTape, Diastix, and Chemstrip uG. Prices vary, so do some comparison shopping.
Urine Test Results
- The result of your urine test is a percentage figure that indicates the concentration of sugar in your urine. The higher the figure, the higher the concentration of sugar. Your test results will vary from one-half % to 5%, depending on the concentration of sugar. Use the percentage value when recording test results.
- When you are in good control, your urine tests should be negative (no sugar) most of the time. A negative urine test indicates that your blood glucose level is probably below 180 mg/ml. Your doctor or diabetes educator may instruct you to call for help when two or more consecutive urine tests show a positive result (1% to 5%).
Recording Urine Test Results
- Keeping a record of your urine test results is helpful. Your record should include date, type of medication, urine test results, and any unusual circumstances such as illness, stress, overeating, or change in activity level. Be sure to bring your record when you visit your doctor or diabetes educator.
REMEMBER: The care of diabetes is a team effort involving you, your physician, and the diabetes education staff where you receive your medical care. This handbook cannot-and was not meant to-replace this team effort.
This handbook embodies the approach of the diabetes care team at the University of Massachusetts Medical School. Different diabetes care teams may approach some aspects of diabetes care in ways that differ from those in this handbook. While most teams are in close agreement regarding the GENERAL PRINCIPLES of diabetes care, they may differ in the DETAILS. There can be more that one "right" way to approach a specific issue in diabetes management.
Always remain in touch with your diabetes care team, and bring any questions you may have about the materials in this handbook to their attention!
Copyright 1995-1999 Ruth E. Lundstrom, R.N. and Aldo A. Rossini, M.D. All rights reserved.
Feedback: send e-mail to Dr. Aldo Rossini