HbA1c, mean glucose, Time in Range


Average - a number expressing the

central or typical value in a set of data,

in particular the mode, median, or

(most commonly) the mean, which is

calculated by dividing the sum of the

values in the set by their number.

HbA1c - when haemoglobin in blood

is measured to identify the three-month

average plasma glucose concentration.

It is limited to a three-month average

because the lifespan of a red blood cell

is four months (120 days). Normal levels

of glucose produce a normal amount of

glycated haemoglobin. As the average

amount of plasma glucose increases,

the fraction of glycated haemoglobin

increases in a predictable way. This

serves as an indicator that average

blood glucose is increasing and that

action should probably be taken.

HRQOL - Health-related quality of life

Mean glucose - the value obtained by

dividing the sum of several quantities

by their number. Average and mean are

often interchangeable. If you want to

know more, read sciencing.com

PROs - patient-reported outcomes

Proportion in range - another number,

it's a way of converting the amount of

time you spend in range into one figure,

and a way of directing control so that

you are aiming for 70% of your readings

being in range.

Time in Range - time spent in the

range between your specified 'high'

blood glucose and specified 'low'

glucose. This could be 4-10mmols, or

it might be a bit broader. The aim is to

limit the extreme highs and lows that

make diabetes so difficult to live with.

So if yours are initially set at 6-12mmols,

then that's fine. Once you're achieving

more TIR, then you can lower those



of 50% time in range when someone

uses CGM. In our data, with at least three

blood tests per day and an average of five

tests per day, we found that an HbA1c of

8% was associated with 50% proportion

in range."

He also says, "Time in range is not

really new, it's just that we've not been

calling it that. Also, we can now look at

time in ranges - high, in range and low.

Looking at data in this way has been a

recent groundswell connected to the

rise in the use of CGM. The myth about

diabetes has been that it's simple - match

insulin to carbs based on a blood test

reading and it should be 'bingo', a perfect

result, but it clearly does not always

work like that. This simple formula does

not allow for exercise, hormones, or the

person's intake of fat and protein when

eating, which can also affect absorption

and the resulting blood glucose level. The

fact is that access to CGM is limited, but

even without CGM if you can aim to get

70% time in range or proportion in range

then this will definitely help with control

In 1967 the television series The Prisoner was aired,

devised by and featuring Patrick McGoohan, who

played the lead role, Number 6. Yet he declared, 'I

am not a number.' Boy, do we know how that feels.

The TIR sign stands for

Transport International

Routiers, as seen on

trucks across Europe.

It indicates that their

contents do not require

customs inspections at

borders, a scheme that

has been running since

the 1940s.



and, in the end, with improved HbA1c

too. Basically, variability - going up, going

down - is problematic. Improve on that,

and it all gets better."

In all likelihood HbA1c will stay around,

not only because it's so embedded

in diabetes healthcare today, but also

because it does have its uses. Getting

better control needs more ways of

being assessed and 'seen' in order that

outcomes can be tweaked in various

aspects of a diabetic's daily life. Greater

clarity of trends could lead to better

control and better quality of life, so it's not

to be sniffed at. It has been found that the

percentage of time spent in range relates

directly to HbA1c, therefore TIR will, in

time, become a means of intervention in


American management guru Peter

Brucker is credited with saying, "What gets

measured gets improved," so bring on Time

In Range. If you're not already talking about

it with your HCP, start the conversation next

time you have the chance.


  1. Desang diabetes magazine diabetes information
  2. Dexcom CGM, continuous glucose monitoring
  3. Desang diabetes magazine diabetes information, Sue Marshall
  4. Desang diabetes magazine diabetes news
  5. Diabetes UK Nutrition Guidelines, Medtronic insulin pump CGM packages
  6. Verily, CGM for T2, Medical ID jewellery, Ascensia Diabetes Challenge
  7. Leicester Diabetes Centre, JDRF, Rachel Connor JDRF, T1Exchange
  8. Diabetes kit diabetes management equipment
  9. Omnipod Insulet insulin pump with insulin pods
  10. Desang diabetes magazine diabetes diet
  11. Desang diabetes magazine diabetes diet
  12. Accu-Chek Mobile blood glucose system
  13. Accu-Chek Mobile blood glucose system
  14. The tyranny of HbA1c time to talk now about Time in Range
  15. The fallacy of average, why HbA1c isn't good enough
  16. ADA Consensus Report Outcome Measures Beyond HbA1C for Type 1 Diabetes
  17. hypoglycaemia, hyperglycaemia, time in range
  18. patient quality of life
  19. Continuous glucose monitoring is showing the limitations of HbA1c
  20. HbA1c, mean glucose, Time in Range
  21. Ascensia Contour Next One Diabetes blood test meters
  22. My Diabetes Kit Debbie Green
  23. My Diabetes Kit Debbie Green, Accu-Chek Roche, Medtronic
  24. My Diabetes Kit Debbie Green, Accu-Chek Roche, Medtronic
  25. London Medical, London Diabetes Centre, private diabetes clinic
  26. Spirit Healthcare, Chris Barker, Leicester, Empower
  27. Spirit Healthcare, Chris Barker, Leicester, Empower
  28. Making Carbs Count chickpeas
  29. Making Carbs Count chickpeas
  30. Accu-Chek Insight insulin pump
  31. Accu-Chek Insight insulin pump
  32. Page 0032

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