Once I was diagnosed with PCOS, the next step was a visit to my Endocrinologist. In that appointment, we discussed the confirmation of my PCOS test results and all the symptoms I had been experiencing. Like most doctor appointments, it is imperative that you share everything you can to give the doctor as much information as possible. While it is never fun to admit all the things that are wrong with you, it is so important to get the best possible diagnosis. Seems easy enough, but I know many people who struggle with communicating this type of information.
After we chatted and he completed a brief physical exam (heart rate, blood pressure, joints) he wrote an order for some blood work. Now, I will tell you that I AM TERRIBLE WITH NEEDLES. (Triple emphasis definitely needed for this point). Going into the test, I really didn’t know what to expect. In my case, that was probably better so that I didn’t chicken out when it came time for the appointment, but I do wish there had been a better resource on the whole procedure.
Here is a breakdown of what exactly a Glucose Tolerance Test is, how my experience went, and tips & tricks to make your experience as good as possible.
What is a Glucose Tolerance Test?
Though no longer routinely used for diagnosing diabetes. The oral glucose tolerance test (OGTT) was the gold standard for making the diagnosis of type 2 diabetes. It is still commonly used during pregnancy for diagnosing gestational diabetes.
With an oral glucose tolerance test, the person fasts overnight (at least 8 hours, but not more than 16 hours). The next morning, the fasting plasma glucose is tested. After this test, the person receives a dose of oral glucose (the dose depends upon the length of the test). Usually, the glucose is in a sweet-tasting liquid that the person drinks.
Blood samples are taken up to four times at different time points after consumption of the sugar to measure the blood glucose.
The classic oral glucose tolerance test measures blood glucose levels five times over a period of three hours. Some physicians simply take a baseline blood sample followed by a sample two hours after drinking the glucose solution. In a person without diabetes, the glucose levels rise and then fall quickly. In someone with diabetes, glucose levels rise higher than normal and fail to come back down as fast.
People with glucose levels between normal and diabetic levels have so-called impaired glucose tolerance (IGT). People with impaired glucose tolerance do not have diabetes.
What about glucose tolerance testing and pregnancy?
While this was not the case for me, the glucose tolerance test is used for the diagnosis of gestational diabetes (diabetes that develops during pregnancy). It may be used if there are equivocal fasting or random blood glucose results, or to screen for gestational diabetes in pregnant women between 24 to 28 weeks of gestation who are not known to have diabetes.
You have an increased chance of developing gestational diabetes if you:
- Have had gestational diabetes during a previous pregnancy.
- Have previously given birth to a baby who weighed more than 9 lb (4.1 kg).
- Are younger than age 25 and were overweight before getting pregnant.
The test may also be used in the postpartum period to detect diabetes in women who had gestational diabetes during pregnancy. Women who had gestational diabetes do not always develop diabetes later in life, but they should undergo diabetes screening at least every three years throughout.
My experience with the Glucose Tolerance Test
Fasting is no fun. At all. I live in Los Angeles and drove down to Orange County where my Endocrinologist is located the night before and had dinner with my family. At the time, I didn’t know what to expect for the test…I just knew that not getting to enjoy my normal Friday night vodka sodas throughout the evening was a bummer.
We woke up very early the morning of the test and the hunger had to be ignored. No caffeine was also pretty rough.
Once we arrived at the Lab, some initial paperwork was filled out (signing away that you won’t sue the hospital in case something goes wrong is always super reassuring, especially when you hate needles.) We were then escorted into a room for testing. At this point, I am dead silent and look like I have seen a ghost. As a typically talkative person, this was a very different behavior for me. I was terrified.
Since it was early in the morning and my fear was empty with no upcoming appointments, they placed me in a room typically used for children. That’s right. I am that much of a baby. I will say they private room with comfortable chair was fantastic, all baby behavior aside.
The technician then described the procedure to me. I will tell you that either by my mother’s intelligence, an act of an angel, or likely both…I had no idea what I was in for. When the technician explained it was going to be 3 hours and I was going to get poked for a new blood draw every 30 minutes, I wanted to bolt. Every 30 minutes?! A new draw?! 3 hours?! Oh man.
At that point, there was no going back. An initial draw was done and I lost it. I started hyperventilating and crying. I know this is quite dramatic for many strong women who have gone through this, but I think that the reality that I had a health concern was really clear at that point. Days of eating nachos at 2 in the morning, drinking whatever I wanted, and just ignorantly cruising through life with carbs were certainly numbered.
After the initial draw and some time, the technician game in with the super sugary glucose drink. I chose the lemon lime flavor and it basically tasted like she dumped a pound of sugar into a Sprite. I was not into it. My stomach definitely hurt from the sweetness, but we had to keep going.
The remaining draws did not go well for me. In 2 of the draws, my difficult veins did not cooperate causing the need for a redraw after redraw. On the last draw, the nurse suggested we place a heating pad on the location of the draw to help the blood vessels to expand so the process would be easier. She was right, but it would have been nice she shared that info earlier on in the process. This is now a tip I will use any time that I need blood work.
Once the test was over, I was exhausted and pretty loopy. My mom ran to the hospital cafeteria and brought my some crackers which were the most delicious crackers I had ever tasted. I wish we had brought something with us from the get go.
After the test, I was exhausted. Initially, we were planning to go out to lunch and then have me go right back to LA. Instead, we went back to my parents’ house for lunch and I went back to bed. For 4 hours. After that, I was mostly back to my normal self, just tired.
What I wish I knew before the Glucose Tolerance Test
Ideal patient preparation and behavior before the test:
- For the glucose tolerance test to give reliable results, you must be in good health (not have any other illnesses, not even a common cold).
- You should be normally active (not lying down, for example, as an inpatient in a hospital)
- You should not be taking medicines that could affect the blood glucose.
- You should eat and drink as they normally would the day before.
- The morning of the test, you should not smoke or consume caffeine.
What to plan during and right after the test:
- The glucose tolerance diagnostic test may take up to 4 hours. Since activity can interfere with test results, you will be asked to sit quietly during the entire test. Do not eat during the test. You may drink only water during this time. Definitely bring something to entertain yourself like music, books, anything to help pass the time.
- If you are like me and have difficulty with needles along with challenging veins, be prepared that multiple attempts for the multiple draws may be needed. I wish that we applied heat to the draw area from the start. If you can, let the technician know you struggle with needles and would like a heating pad. Or simply bring your own heating pad to help be sure that you will be set.
- After all that fasting, you will be hungry. Be sure to pack a snack that you can eat right after the test. Cheese crackers were my saving grace.
- You are going to be tired and perhaps light headed, so have someone come with you who can drive you home.
What to expect after the test:
Each year, 1% to 5% of people whose test results show impaired glucose tolerance actually develop diabetes. Weight loss and exercise may help people with impaired glucose tolerance return their glucose levels to normal. In addition, some physicians advocate the use of medications, such as Metformin (Glucophage), to help prevent/delay the onset of overt diabetes. Studies have shown that impaired glucose tolerance itself may be a risk factor for the development of heart disease, and whether impaired glucose tolerance turns out to be an entity that deserves treatment itself is something that physicians are currently debating.
- Normal response: A person is said to have a normal response when the two hour glucose level is less than 140 mg/dl, and all values between 0 and 2 hours are less than 200 mg/dl.
- Impaired glucose tolerance (IGT): A person is said to have impaired glucose tolerance when the fasting plasma glucose is less than 126 mg/dl and the two hour glucose level is between 140 and 199 mg/dl. This is sometimes referred to as “prediabetes” because people with IGT have a higher risk of developing diabetes.
- Diabetes: A person has diabetes when two diagnostic tests done on different days show that the blood glucose level is high. This means either the two hour levels is greater than 200 mg/dl or the fasting glucose is noted as greater than 126 mg/dl. A glycosylated hemoglobin (HbA1c) level of 6.5% or more also supports a diagnosis of diabetes mellitus.
- Diabetes during pregnancy: A pregnant woman has diabetes if she has a fasting plasma glucose of over 92 mg/dl, or a two hour glucose level greater than 153 mg/dl.
More to come on my follow up appointment and the medication I was prescribed!
Here are some of the great resources that helped inform my article: