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Date of last update: 10/17/2017.

Forum Name: Diabetes

Question: Help with interpreting results of my glucose tolerance test

 satie85 - Fri Aug 13, 2010 7:45 am

Hi there

I've been feeling increasingly odd of late. I went to my docs and had some checks done, including celiac which came back negative. The other blood work that was done was liver function test for which it came back with an elevated level of ALT (70), been like that for about 10 years though.

So I decided to self administer myself a GTT after reading a book about hypoglycemia, certainly a lot of the symptoms I was experiencing seems to point to hypoglycemia.

I would appreciate a professionals opinion on my GTT testing, even if its just an opinion. After doing a couple of GTTs, I'm not so sure it is indicative of hypoglycemia, but more prediabetic?

Test 1 (12/aug/2010)

Time | glucose (mmol/L) | comment
9.49am | 6.1 | fasting glucose level
+30mins | 8.4 | first reading after consuming 75g of glucose
+1 hour | 9.0 |had a drink of water at this point
+1 hour 30 mins | 7.1 | slight physical activity (10 min drive)
+2 hours | 7.8
+2 hours 30 mins | 5.9

I found this first set of results a little troubling, e.g. a fasting glucose level of 6.1. The previous night to the test at 8.42pm I drank a fruit smoothie (450ml) which contained 16.6g of carbohydrate of which 12.1g of naturally occurring sugars. Note 13 hours 7 minutes elapsed between that drink and first glucose reading at 9.49am the following day. I wondered whether having this drink may explain an elevated glucose level?

I decided to repeat the test the following day, here are the results, which look slightly better:

Test 2 (13/aug/2010)

Time | glucose (mmol/L) | comment
9.09am | 5.0 | fasting glucose level
+30 mins | 9.9 | first reading after drinking 75g glucose only drink
+1 hour | 9.9
+1 hour 30 mins | 7.4
+2 hours | 5.8
+2 hours 30 mins | 6.4

I thought these results looked better than the first set, however, I am slightly confused over why at 2 hours it went right down to 5.8 then 30 minutes later it was up again to 6.4. Perhaps it was just an inaccurate reading. All I was drinking was water, the previous night I last ate an evening meal at 6.30pm and also spent 10 minutes on an exercise bike (max heart rate 144 bpm). After the end of test 2, I went and did a few jobs and when I returned home, I decided to take another sample at 12.29pm (which is 50 minutes since the last reading on test 2 of 6.4 mmol/L), the glucose level at 12.29pm was 4.4.

I am using a digital glucose by accu-chek and took my blood samples from my fingers on both hands.

These results don't seem to indicate a hypoglycemic condition. Because I seem to feel unwell after eating (sometimes), such as disorientation, light headed, mood change, detachment from surroundings, I am wondering whether a rapid rise in blood sugar levels could cause these kinds of symptoms? I appreciate that these symptoms may also be the result of an allergy (I know its not gluten so far).

I don't smoke. I havent drank alcohol for about 6 weeks (trying to get to the bottom of why I feel unwell). Fairly healthy diet, drink lots of water, green tea and one cup of coffee per day. Take a good multivitamin and omega3. Last week started exercising every other day for 30 minutes a time at 75% max heart rate (144bpm for me). Im just under 30 years, weigh 170 pounds (5 foot 10inch tall), I always seem to put weight on in abdomen (so called potbelly) and even with exercise it is proving difficult to get rid of.

Any opinions, insights and advice would be much appreciated.
 Dr.M.Aroon kamath - Sat Aug 14, 2010 9:24 am

User avatar Hi,
The 2 hour and 3 hour OGGTs are generally recommended due to the following reasons.
- in some normal individuals, the rapid emptying of the stomach contents(glucose) into the duodenum tends to cause a sudden large glucose level spike initially, before settling down by about 2 hours due to insulin action.
- in others with slow gastric emptying, the initially the spike is low and the entire OGGT curve may remain rather 'flat'.
Homeostatic mechanism are not instantaneous.It takes a while for the initial spike to be brought down by the insulin action.
This is why the 2 hour value is considered as most crucial.

The 2 and 3 hour OGGTs have been subject to considerable disagreement as to their interpretation.

Your first OGGT values may be interpreted as impaired fasting glucose (IFG). Generally,if results indicate a IFG, an annual fasting blood glucose determination is recommended. The second test (done the very next day) shows normal values.

However, since you are concerned about being overweight, you should have your fasting blood glucose checked annually.

It takes sometimes years to accumulate fat, therefore it is not surprising that it will take a while to get rid of the excess as well. You need to persist with the dietary measures and exercises in order to be successful.
Best wishes!

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