Diabetes - What To Test

Certainly, the blood sugar should be tested if the person feels unusual or ill. Besides the regular testing practices (a minimum of three to four times a day, three days a week for those with Type 1 diabetes; a minimum of four times a day, one day a week for those with Type 2 diabetes), other tests should be added as needed.

(Remember, it has been found that the more information you get from more frequent testing, the better you are able to use that information to control your blood sugar.) If blood-sugar test results are 250 mgfdl (14 mmol) or greater, most health professionals would advise that you test the urine for ketones. If you are ill, they would usually advise that you test for ketones in the urine even if your blood-sugar levels are not high. If you are preparing to exercise and find blood-sugar levels of 250 mgfdl (14 mmol) or greater, you should test for ketones to determine whether or not you should exercise. Urine testing for glucose is seldom recommended anymore. The major reason is that an elevated or lowered renal threshold will give false information. The renal threshold can be determined by emptying the bladder and testing this urine with the taking of a concurrent blood-sugar (glucose) test. You should then eat a meal, testing the urine and blood sugar 1 hour, 2 hours, and 3 hours afterward. The renal threshold is determined by matching each blood-sugar result with the urine test that follows it (not the urine test taken at the same time as the blood-sugar test). The normal renal threshold is at blood-sugar levels of 160-180 mgfdl (9-10 mmol). Children and pregnant women often run renal thresholds of less than 160 mgfdl (9 mmol). Elderly people have a tendency to have renal thresholds greater than 180 mgfdl (10 mmol), and often greater than 200 mgfdl (11 mmol). Remember that damage to blood vessels and nerves begins at blood-sugar levels above 150 mgfdl (8 mmol), so a person with a renal threshold of 200 mgfdl (11 mmol) could have a negative urine test for sugar (glucose) and still be developing complications. If blood-glucose tests are unacceptable and the renal-threshold level is known, information from urine glucose tests is helpful. Certainly, such information is better than no information at all. Note that a value obtained from a second passing of urine will measure sugar more nearly representative of what is found in the blood at that time. The first voided test lets the person know what sugar has accumulated over a period of time, and therefore provides a better measure over time. Many times, the second voided urine will contain the same amount of sugar as the first urine specimen (such as 33 percent). (For children staying on the "spilling side" of negative, use a strip or stick method, related to normal or nearnormal glycosylated hemoglobin tests in our patient population.) While urine testing for sugar has limited value, it is useful for small children who have tender fingers or for those individuals who have normal renal thresholds. Urine testing for sugar is of practically no value in adults, especially in the elderly. This brings us back to blood-sugar (glucose) testing. The glycosylated hemoglobin test gives the best overall, average determinations of blood-sugar levels for the longest period of time. The hemoglobin A1 test (upper limits of normals are around 8 to 9 percent) includes the components or parts of A1a, A1b and A1c .It is found to respond better to more recent increases or decreases in blood0-sugar levels than does the more stable component of this test, the hemoglobin Ale (upper level of normals are around 6 to 7 percent). There are problems with these tests, however. They can be influenced by sickle-cell disease and other abnormalities of hemoglobin (thalassemia, fetal hemoglobin) and by abnormally high or low hematocrits (the low hematocrit reading will result in a falsely low glycosylated hemoglobin Ale; a high hematocrit reading will result in a falsely high glycosylated hemoglobin Ale reading). If home blood-sugar tests over the past 2 to 3 months do not seem to match the results of the glycosylated hemoglobin Ale, then be concerned that something else may be occurring (for example, problems with the machine, with the method or accuracy of the testing, or with hemoglobin or hematocrit levels). Most health professionals prefer to check the hemoglobin Ale every 3 months. As noted earlier, fructosamine and glycosylated-serum protein levels demonstrate average blood-sugar levels up to about 2 to 3 weeks. The first test measures the glucose levels associated with the albumin in the blood; the second measures the glycosylation that has occurred in the other proteins found in the serum of the blood. The second test is more stable than the first, but it is also more expensive. The upper limit of normal for the fructosamine test is 2.8 percent, and for glycosylated protein it is about 8 percent. Daily self-testing of blood-sugar levels gives the most information. These tests can demonstrate a pattern that may be a reflection of food and medication and of the interactions of these with the person's activity and stressors at home or work. There is a concern about immediately responding to a test result with an increase or decrease of insulin. For a small child, unless he or she is ill, predicting the activity after the extra dose has been given can send the child diving into an insulin reaction. Withholding a dose of insulin because the blood-sugar test is in the normal range may start a series of events leading to a roller-coaster type of response (or to what is termed "rainbow therapy" by some, meaning that you are always chasing the pot of gold at the end of the rainbow but never catching it!). The algorithm method of insulin adjustment is at least based on the giving of insulin over and above the usual baseline daily dose. The person is thus not left with the situation.of receiving no insulin and then having to play "catch-up" at a later time. Unless the person is ill, when supplemental insulin is used to respond to high blood-sugar levels in order to keep the person out of diabetic ketoacidosis, infrequent blood-sugar "spikes" may represent one-time emotional responses and therefore do not require an immediate response. If a pattern develops in the elevation or lowering of blood-sugar levels, something should be done before that blood-sugar response occurs rather than after the fact. Using this approach, health professionals teach people to review their records every two to three days and make adjustments to affect patterns that are observed. Those professionals who use the algorithm approach individualize the amount of insulin to be given when the blood-sugar levels are 150 mg/dl (8 mmol) or higher. If this extra insulin is needed frequently, it is added to the previous dose. For the adult, a combination of both of these methods may be successful.