How to prepare for a blood glucose test

Are you prepared for your Blood Glucose Test?

Yes, I know blood glucose test isn’t a war for which you need to prepare, rather blood glucose tests are very simple and easy process to diagnose your diabetic condition. But to get accurate conclusive results there are some points that can really affect your tests.

are you prepared for blood glucose test

So, whenever you go to the hospital for a blood glucose test or take test yourself, it is very important that you know and understand the method, precautions necessary for the tests such as:

1) If you are going for a random glucose test, you may eat and drink normally as you do but don’t overdo on high sugary drink.

2) If you will be taking a fasting blood glucose test, you must not eat or drink anything other than water for eight hours before the test. It is much better if you can schedule your fasting glucose test early in the morning so you can have overnight fasting and  will not have to fast during the day.

3) It is very important that before the test or when scheduling for it, you tell your doctor about any other health condition and medications you are taking, including prescriptions, over the counter drugs and even any other herbal supplements. Some medications can affect blood glucose level and give false readings on the test. So, your doctor can take this into consideration and tell you to stop taking any particular medication or change the dosage before your test temporarily to minimize the effect on the test.

Medications that can affect your blood glucose levels and the test include:

  • Steroids
  • Birth control pills
  • Aspirin
  • Epinephrine
  • Acetaminophen
  • Phenytoin
  • Corticosteroids
  • Atypical antipsychotics
  • Tricyclic antidepressants
  • Lithium
  • Diuretics
  • Monoamine Oxidase Inhibitors (MAOIs)
  • Sulfonylurea medications
  • Hormone therapy

High stress is another reason for high blood glucose levels temporarily. It is very important that you tell your doctor clearly if you had any of these recently:

  • Heart attack
  • Stroke
  • Trauma
  • Surgery


Blood Glucose Tests for Diabetes Type 1 and Type 2:

To determine more accurately if you have diabetes or not, doctors normally take one of the 3 tests (or all of them in some cases where one test is inconclusive due to some underlying health condition or medication) for a better conclusive analysis.

1) A1C Test: This blood test is called Glycated Hemoglobin A1C Test. This gives the doctor your average blood sugar reading for the past three months. It calculates the percentage of blood glucose attached to the hemoglobin and the oxygen carrying protein in red blood cells (RBC). Higher blood glucose level results in more glucose attached to hemoglobin proportionately.

An A1C level of 6.5 percent or higher on two separate tests indicates that you have diabetes. An A1C between 5.7 and 6.4 percent indicates prediabetes. And A1C level below 5.7 percent is considered normal condition. 

Glycated Hemoglobin A1C Test Result readings


2) FPG Test: This blood test is called Fasting Plasma Glucose Test also known as fasting glucose test (FGT). In this test, your doctor will take a blood sample after an overnight fasting or several hours of fasting to measure blood sugar levels. This is mostly taken in the morning, so you don’t have to starve in the day for the test.

A fasting blood sugar level of 126 mg/dl (7 mmol/L) or higher on two separate tests indicates that you have diabetes. A FPG level from 100 to 125 mg/dl (5.6 to 6.9 mmol/L) indicates prediabetes. And FPG level below 100 mg/dl (5.6 mmol/L) is considered normal condition.

Fasting Plasma Glucose Test Result readings


3) OGTT Test: This is called Oral Glucose Tolerance Test. This is two stage test in which first you fast overnight and then the first blood sugar level is measured. After that you take a sugary drink and then your blood sugar level is measured for the next two hours. This gives a better reading of the blood sugar spike caused by the drink from normal to highest.

An oral glucose tolerance test level 200mg/dl (11.1 mmol/L) or higher after two hours indicates that you have diabetes.  An OGTT level from 140 to 199 mg/dl (7.8 to 11.0 mmol/L) indicates prediabetes. And OGTT level below 140mg/dl (7.8 mmol/L) is considered normal condition.

Oral Glucose Tolerance Test Result readings

In case of your doctor suspect Type 1 diabetes, a further urine test might be necessary to check for the presence of a byproduct produced during muscle and fat tissue used to generate energy when body cells don’t have required insulin to break glucose. With this, your doctor will more likely run a second test to determine if you have destructive immune system cells associated with Type 1 diabetes called Auto-antibodies.


Blood Glucose Tests for Gestational Diabetes:

Gestational diabetes occurs during pregnancy, so your doctor will determine your condition based on some risk factors such as:

You may have high risk of gestational diabetes, if:  

1) You had gestational diabetes during your previous pregnancy.

2) Any of your family member – mother, father, sibling or a child has diabetes.

3) You were obese at the start of your pregnancy.

If your doctor finds a high risk factor that can affect your gestational diabetes, he can ask you to take a blood glucose test at your first prenatal visit to prevent any further complications.

If your doctor doesn’t find a high risk factor, it will be better to take a screening test for gestational diabetes anytime during your second trimester which is typically between 24 to 28 weeks of pregnancy to keep it in check depending on your doctor’s advice to prevent any complications later.

Your doctor will take following two tests to determine your blood glucose levels and the condition:

a) Initial Glucose Challenge Test:  In this test, you will have to drink a sugary glucose solution. After one hour, there will be a blood test to measure your blood sugar level. If your glucose challenge test result is below 140 mg/dl (7.2 to 7.8 mmol/L), it is considered normal and it’s a very good news. However, if your test result is higher than normal, it only means you have a higher risk of gestational diabetes. To give a more accurate diagnosis, your doctor will order a follow-up glucose tolerance test to determine if you have gestational diabetes or not.

b) Follow-up Glucose Tolerance Test: For this test, you will have to fast overnight or more than eight hours and then take the blood test to measure your fasting blood sugar level. After than you will have to drink a sugary solution which contains a high concentration of glucose and then your blood will be tested for every hour for a period of three hours to measure your blood sugar level at three times. If at least two of the blood sugar level results are higher than normal as per readings established for each of the three hours of the test, that means you have gestational diabetes.

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