Very scary situation that I can't explain

The other day I was having a good day with all my numbers between 4 and 6 (mmol/L or between 72 and 108 mg/dl), that is until diner. I was at 5.5 (99) before my meal, did normal insulin for a normal meal that I've had before. I left to head out and finish some studying at school about an hour later, on my walk to school I decided to test my blood just because I was curious but felt absolutely fine. My meter read 1.9 (3.4)! I was absolutely panicked and immediately took 4 tablets of dex4. I finished walking to school and tested 15 minutes later and was at 15 (or 270). This was about an hour after my injection of humalog, none of it adds up. I never have spikes like that, my monthly average is 6 (108) and my control is pretty good.

I know that my meter has a bit of trouble when it's really really cold out but it is still extremely worrying. The way I spiked up its almost as if I didn't need the dex4 and my meter was wrong. To jump 13 mmol/L in 15 minutes while my humalog is peaking for just 16g of sugar just doesn't make sense.

If anyone has any ideas or similar experiences, let me know!


Hi Patrick

It is frustrating to have numbers that bounce around for no apparent reason.  It is hard to explain to other people who are close to you why that happens, also.

The best way to troubleshoot odd meter numbers is to test with another meter if you have one.  If there is a big discrepancy between the meters, you will know to replace the defective meter.  I have had experiences of being really hungry but when I test  the reading is above an acceptable level to eat.  It is also difficult to give a correction bolus, wait the appropriate amount of time, and see an even higher reading.  I have also had the experience of feeling 'fine' ( as I say to my wife who usually will know I'm not fine) and having a low blood sugar.

Just some of the joys of being a T1.



If I get a weird reading I usually test again on a different finger to see if it comes up the same.  I tested at 22 one time, and was so confused.  Turns out I had jam on the finger I tested with...

I also get a meter check done with my blood work every 3 months.  They get you to check your sugar with your meter and write down what it says.  They will give you a call if it's different than what they get from your blood sample.

I think you're meter was wrong with the 1.9.  And I think your subsequent panic + dex tabs caused the spike.  But you may never figure out what happened.  Don't worry too much - remember: if your bloodsugar was normal all the time, you wouldn't be diabetic!

Agree with the person who said to test again when you get a "funny" reading. I get fairly strong symptoms when my blood sugar is low, so am more likely to believe my body then a meter. BUT, if I tested again and got a low reading, then I would believe my meter.

Typically, I have more "wrong" readings that are too high because I have some sugar on my fingers. I rarely get "wrong" readings that are too low, but it has happened to me in the past.


meters can be wrong, but tend to be more accurate at lower blood sugar levels.  Extreme cold can affect meters, mine will boot with an error if it is too cold.

here's another possibility - walking while I have insulin on board can drop my blood sugar very fast.  If I know I am going to be walking at about an hour after I eat, I may only bolus for about half my meal.  it works for me. 

don't discount your own glycogen causing your spike.  a fast drop in bs can cause your liver to dump all the sugar storage, causing the same massive spike as a glucagon shot.   it's a nice thing really, if it was your liver sugar storage coming to the rescue.

I have had a bad test too. I have also had a later spike with certain carbs. If I eat pasta or pizza (typically higher fat because of cheese), I will not spike until 2 hours after a meal. This can be frustrating since I may bolus and actually have a low before my meal carbs spike me... 

My advice - pick a part what you ate. Maybe you can see a trend?