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 - Your Guide to Good Control
- 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.
Equipment for SMBG
- Lancet Device
- Lancets
- Test Strips
- Meter/Sensor
- Alcohol Wipes (optional)
- Log Book
- Optional equipment: a computer and software for analyzing results that are stored in the memory of most new meters.
SMBG Instructions
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 or
- Clean the area with alcohol and dry completely (optional).
- 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.
What should my blood glucose levels be?
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:
| Time: |
Excellent |
Good |
Fair |
Poor |
| Before a Meal (or fasting) |
60-100 |
100-140 |
140-180 |
over 180 |
| After a Meal |
110-140 |
140-180 |
180-220 |
over 220 |
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.
Recording SMBG Results
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.
SMBG Meters and Sensors
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.
Choosing a Lancet Device
Self-Monitoring of Blood GlucoseSome 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.
