When we talk about glucose, referring to a health issue, diabetes immediately comes to mind, and the imbalance that occurs in this disease with reference to glucose levels (better technically called “glycemia”) in the blood of those who suffer from this disease in its various forms. In order to characterize the state of health related to blood glucose levels, we must access these values through specific laboratory tests. In this case, the two tests that are primarily performed to measure blood glucose levels are, first, the blood glucose test. basal glucose, or basal glycemia, also called fasting glucose tolerance test or fasting plasma glucose test. The second diagnostic test for blood sugar levels is called postprandial glucose test.
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What is the difference between the basal glucose test and the postprandial glucose test?
Both tests are important to characterize the metabolic state of the patient, but they are based on the particular metabolic condition of two different moments in which the body is faced with the glucose circulating through its vascular system. Let’s see what each of these tests is about and what information they provide in each case.
- Basal glucose or fasting glucose tolerance It is a test that is performed after the patient’s body has been subjected to a severe fast for at least 8 hours, only being able to ingest water during that period and until the blood sample is taken for quantification.
This test, as its name expresses it, shows baseline blood glucose values, fasting, before eating.
- In contrast, the postprandial glucose test is performed after two hours have elapsed after the patient has ingested a controlled sample of foods rich in glucose, after having also passed a minimum of 8 hours fasting. Usually a glucose solution of known and standardized concentration is administered, equivalent to 75 g of glucose dissolved in 300 ml of water.
- A third very useful test, which is performed on occasion, is that of the glycosylated hemoglobin (HbA1c). It is a much more accurate and informative test than the previous ones, as it is capable of detecting the average level of glucose in the blood during the last three months.
Of the three mentioned tests, the basal glucose test is the one that is performed routinely, due to its ease of implementation and lower cost than the other two.
Let’s now go on to review what are the values that specialists (WHO and the American Diabetes Association) have determined as critical levels to classify a glycemic index as low, normal or high, and its consequences on health.
Accepted values in normoglycemia
There are reference values for the measurement of basal blood glucose in two different circumstances; if the test is performed having previously kept the appropriate fast, or if, on the other hand, the test is performed occasionally, without having had the opportunity to keep the previous fast.
- In the first case, when there is a previous fasting, the value estimated as normal for basal blood glucose should not exceed 100 mg / dl (5.6 mmol / l) (millimoles per liter).
- If the glucose test it is done in a way random, not having respected the fast, the results will depend on the amount of carbohydrates ingested in the last meal and the time elapsed from this until the sample is taken. In general, there is a convention that a maximum of 125 mg / dl (6.9 mmol / l) is an acceptable value for this test, although it would be indicated to repeat it while fasting and then going to a medical appointment, since the accepted values as more suitable they are around 80 mg / dl and should not exceed 100 mg / dl.
Values considered as hyperglycemia
- Maintained altered basal glucose levels in values ranging between 110-125 mg / dl (5.6-6.9 mmol / l) are considered as a prediabetic condition and they deserve strict medical control.
- Basal glucose levels equal to or greater than 126 mg / l (7 mmol / dl), or values equal to or greater than 200 mg / dl in randomized trials, are already considered established type 2 diabetes.
- Often times the type 2 diabetes it is accompanied by three characteristic symptoms that contribute to its diagnosis, together with blood glucose values; It’s about the polydipsia (permanent thirst), polyuria (urge for frequent urination) and the unexplained tendency to lose weight, despite maintaining a good appetite.
Standard Values for Hypoglycemia
- If taken strictly, hypoglycemia should only be considered when basal glucose values are below 55 mg / dl, except in people with diabetes, whose minimum values do not usually fall below 70 mg / dl, although they sometimes achieve reduce it to 60 to 65 mg / dl.
- We must be careful with these reductions in glucose in diabetics, especially if it is sudden, and may be accompanied by dizziness, and even fainting, because even when the drop in the value of said glucose is not at minimum values, a diabetic patient perceives values still high in glucose for themselves -but lower than their normal altered values- as if it were hypoglycemia.
Importance of basal glucose control for health
If the hyperglycemic condition persists uncontrollably, eventually the sugar in the bloodstream produces the deterioration of the cardiovascular system, causing pathologies such as hypertension and heart and circulatory diseases (up to the possible advent of cardiac arrest), formation of diabetic ulcers (particularly in the lower legs and feet), kidney failure, vision difficulties until culminating in blindness from optic nerve damage, Y damage to the nervous system, particularly in the peripheral nerves, more frequently in those of the fingers and toes.
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