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If a doctor's concerned if a patient has diabetes or is at risk for diabetes

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they might suggest an A1C test to be performed

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What I want to do in this video is to explore what A1C even means

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and also how that actually relates to diabetes

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or the main side effect of diabetes, which is having high blood sugar, or "hyperglycemia"

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So to do that, let's think about red blood cells

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and I know what you're thinking: what is this to do with diabetes?

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we'll get there in a little bit

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So red blood cells are the main oxygen carriers in our blood

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they kind of look like these lozenges

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and inside a red blood cells

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you have hundreds and millions of haemoglobin molecules, or haemoglobin proteins

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So let me draw some haemoglobin proteins

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Actually we have, the number I found is, 200-300 million per red blood cell

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and then we have tens of trillions of red blood cells, so we have a lot of haemoglobins in us

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and haemoglobin is what makes red blood cells red

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When haemoglobin is bound to oxygen, it has a red colour

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This right here, each of those are haemoglobin proteins

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Now, it turns out, a haemoglobin, let me draw a bigger version of it... haemoglobin

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If it has some glucose around, so let me draw some glucose floating around near the haemoglobin

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If it has some glucose around, there's some chance

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it's not a high probability, but there's some chance

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that the haemoglobin and the glucose bump into each other

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at just the right way that they'll bind to each other

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And so you'll have this situation where you have glucose bound to the haemoglobin

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Now this haemoglobin with the glucose bound to it, is called "glycated haemoglobin"

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I wrote "glycated" in green, 'cause I'm using green for the glucose

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Another name for glycated haemoglobin, or haemoglobin that has some glucose bound to it

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is "haemoglobin A1C"

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And now I can imagine things are starting to click in your brain

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When you're measuring your A1C level, that's a test of the percentage of your haemoglobin that is haemoglobin A1C

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So you take a blood test, they're measuring relative to the total amount of haemoglobin

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what percentage of that is haemoglobin A1C

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And a normal range of that, so if just have normal blood sugar for a reasonable amount of time

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you're going to have a haemoglobin A1C level in kind of a 4-6% range

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And people are still kind of trying to tighten up this range

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and it doesn't completely correlate tightly with the blood sugar

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Well, it does correlate, but still, people of the same blood sugar can still have fairly different A1C levels

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But 4-6% is considered normal

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And if you have higher, higher than 7 or 8%

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so greater than 7 or 8%, so if you have like an A1C level of 9 or 10%, that's high

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So you can imagine this is kind of a proxy for how much glucose you have in your bloodstream

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because the more glucose you have in your bloodstream

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the higher the probability that that glucose is going to react with the actual haemoglobin

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so you're going to have a higher percentage of haemoglobin A1C

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And the other reason why this is useful is kind of, well I guess you can see on the first pass

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it's useful because not one of these snapshots that test

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everything we've talked about so far, with respect to diabetes

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is taking your blood sugar at any one point in time

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and we know that your blood sugar changes through out the day

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changes depending on how active you are

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changes depending on what you might have just eaten

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so when you do blood sugar, you're just getting a sample

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you don't know where the blood sugar is through out the day, unless you just kept sampling

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which can get pretty annoying, you know, keep pricking your needle

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With A1C, this starts to become a measure of how much glucose you've had in your blood

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over a longer period of time

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And in general kind of uses for a measure for the last few months

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because the red blood cells and the haemoglobin in them

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they have a life span of about 120 days

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That obviously doesn't mean all of your haemoglobin gets produced on one day and all dies 120 days later

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you have some red blood cells and haemoglobin that might be a few seconds old

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and then you have some that might be approaching 120 days old

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so on average they're going to be around 60 days old, or about 2 months old

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So on measuring this percentage, you're definitely not getting the percentage of anything older than 120 days

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and on average you're seeing things that are from about 2 months old

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So the higher this percentage, this is saying:

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Wow, this is, you know, my average haemoglobin molecule in my body is only maybe 60 days old at this point

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And already 7-8% of them have already been glycated

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which is an indicator that I probably have more blood sugar than a normal person

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In normal situation, only 4-6% of my haemoglobin would get glycated

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so hopefully that explains what A1C is

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But I do want to say, and I said in the beginning of the video, that I'm not a doctor

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and even amongst doctors, the A1C test, or the A1C measurement

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there's some debate about how useful it is, what it's measuring

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or kind of how far back it actually is a good view at kind of your glucose levels

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And also, as I've mentioned, two people with the exact same blood sugar could have different A1C levels

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depending on other things: how old they are, whether they have some other type of medical condition