The HbA1c test uses RBC exposure to sugar as an indication of whole body glucose exposures. It works like a charm, as long as your red blood cells are healthy
Click to listen to the audio…
Too much glucose is toxic…..
Especially to cells that struggle to control, just how much glucose comes in.
Now for the record, that isn’t every cell.
Clearing the sugar
Most actually have sophisticated systems to manage just how much sugar swirls in. And, when the sugar floods in, the sugar is channelled as appropriate.
So for example………
A muscle cell can use the sugar or stash it away, for the next sprint for the bus or that 90 minute zumba class. When there isn’t going to be much of a call for sugar, it closes the door. Making the excess sugar, SOMEONE else’s problem.
Whose problem is it ?
The someone who takes the most strain, in the short term, at least – is insulin. Since it’s his job to put away the groceries, he’s got to get them out of the circulation and stored away safely.
Of course, his “solution to the problem” does have ripple effects.
And this “problem/solution” compounds over time….. leading to big bellies on the outside.
Contributiong to blockages
We’re accustomed to blaming cholesterol, for cardiovascular problems, because cholesterol is the molecule that IS SEEN. But it takes two to tango………….
And sugar molecules are RIGHT THERE in the thick of things.
Along with a crazy busy overwhelmed insulin, who is actively being RESISTED.
The sugar processing hub
Liver cells, have more options that most. In addition to burning it for fuel and storing it as glycogen, liver cells can do a little chemical feneekery and turn the sugar into fat.
Fatty liver disease anyone ?
But, it’s the cells that can’t handle the sugar, that suffer the most.
Limited sugar processors
They just choke on the sticky onslaught…..
The cells that take SERIOUS strain from the high sugar levels are found in the
These are the organs that suffer significant harms, developing terrible opathies, that devastate lives, when glycemic control goes out the window.
On a mission
Saving the vulnerable is the objective, which is why doctors focus their attention on glycemic control.
Sugar levels MUST be kept, in a normal range.
Deviations cause DAMAGE !
Tracking sugar levels
To manage sugar levels appropriately, YOU MUST monitor just how much glucose, the average at risk cell is experiencing. Logic says that the easiest way to do this is to measure the amount of sugar in the blood.
But it is complicated………..
- First off, it hurts.
- And it’s time sensitive, because glucose levels oscillate, as the body manages sugar availability, based on supply and demand.
Failure is relative
Yes, the management is pretty ineffectual in someone with type 2 diabetes.
But it is not NON-EXISTENT.
Insulin does show up and the sugar is cleared, EVENTUALLY.
NOTE : In the type 1 diabetic it’s a free for all, with little to no attempt at management, because the commander in chief is AWOL. So hungry cell melt downs, co-exist with sugar poisonings.
The point is………..
Timing is important
To keep tabs on the sugar levels, you need to time your testing, PERFECTLY.
This is something the professional diabetic is trained to do. Anyone who is managing their diabetes with insulin, is issued with a blood glucose meter or hooked up to a CGM (continuous glucose monitoring) device. This precision is not a nice to have, it’s a necessity.
Getting the insulin mix WRONG, can kill you.
You must be “a professional”
But, it’s not considered a necessity for the diabetic who is managing their diabetes with glucose lowering meds. And Jo Soap the public, doesn’t have a glucose meter in their pocket.
Which leaves the dilemma……
How does your doctor KNOW what is going on, when you arrive at his office at 10.30 am on a Wednesday morning ?
The spot blood test
A spot blood test is fraught with difficulties. If you’ve just had tea and a biscuit, your sugar WILL BE HIGH. Eish !
Time to go to plan B…
The OGTT (oral glucose tolerance test)
For years, this was the only option to diagnose type 2 diabetes. You would be told to come back tomorrow fasted, to do an oral glucose tolerance test.
But this would mean more time off work, more angst…………..
And now, the added “complication” is SOCIAL DISTANCING. Eish !
Enter the HbA1c test
It’s a simple blood test that can be done, anytime of day or night, which tells the story of sugar exposures, not just in the moment, but for the last 3 months.
The sugar exposure is that of the red blood cell, an easily accessible set of cells.
Easy does not mean painless !
On paper at least………….. IT’S PERFECT.
Red blood cells stand proxy
So what is the deal ?
Red blood cells aren’t officially vulnerable to glucose toxicity.
They run on sugar, in fact, they are one of the few cell types that don’t have a choice. They run their biology, by splitting sugar (glycolysis) and the sugar they use, swirls in, via the GLUT1 gate.
There is no resistance
Since the GLUT1 gate offers NO RESISTANCE, how much sugar enters is directly proportional to how much sugar is in the circulation.
But when the sugar gets inside, it can leave a mark.
Click here to learn more about this chemistry and it’s consequences.
Haemoglobin gets glycated
The job of hemoglobin, is to carry oxygen around the body, to do this, the red blood cell is full of haemoglobin. Structually haemoglobin is made up of 4 protein chains : 2 alpha and 2 beta chains. It turns out, the beta chains have a valine amino acid residue, right on the end of the chain and this is the spot, where the chemistry happens.
There is nothing particularly special about the beta globin protein – sugars are “reactive” and most proteins have vulnerable spots, that can and do, take a hit.
Counting glycated proteins
In most cases, glycated proteins are extremely hard to measure, because the concentration of the protein, that has been glycated is already extremely low and the number of jammed on sugars is tiny.
It’s like looking for a needle in a hay stack.
But red blood cells are effectively “bags of haemoglobin”.
It’s this that makes them useful.
Bags of haemoglobin
The fact that there is lots and lots of haemoglobin, changes the dimensions of the needle and the hay stack. It becomes possible to measure the number of haemoglobin molecules, with a sugar jammed on.
Around 5 % of the globins have been glycated.
If sugar levels are higher, this number rises in proportion to the increased sugar level.
NOTE : A number > 6.5 % will get you a diagnosis of type 2 diabetes.
And so………. the HbA1c gives us a way to “spy” on sugar exposures, across the whole body. It works like a charm.
As long as your red blood cells and haemoglobin levels are NORMAL.
But what if they’re not………
Red blood cell abnormalities
Make interpreting the HbA1c test results – CHALLENGING.
And on occasion, this can lead to THE WRONG DIAGNOSIS !
Look at the big picture
The HbA1c test should never be THE ONLY TEST used to diagnose diabetes and/or monitor glycemic control. It is a very important piece of the puzzle, but it is just A PIECE. When it comes to creating BETTER BODY CHEMISTRY and BETTER HEALTH….
You need to keep an eye on THE BIG PICTURE.
Want some help managing your glycemic health without drugs, head on over to the “Suppressing sugar spikes” library page. You’ll find several suggestions that will help you keep carbs on the plate, when you are metabolically challenged. Plus a HbA1c tracker you can download.
HbA1c: More than just a number. AJGP (2021) 50 (9) : 628 – 632. Mawson Wang, Tien-Ming Hng.