Adjusting insulin dose.. glucose control

David Kinshuck





What is good blood glucose control?

Good control of blood glucose is needed to


What is good blood glucose control?..'targets'

When your test your own blood glucose you need to aim for detail , and aim for

This will keep blood glucose levels as near to the normal range as possible without causing problems such as hypos.

Occasionally, you may find that your blood glucose reading is high, e.g. 13 mmol/l. As  long as you fell well and it returns to an acceptable level when corrected, this unlikely to cause any harm.


HbA1c (Gylcated Haemoglobin)

See   Glucose sticks to the red blood cells and tissues of the body. The higher the blood glucose, the greater amount of glucose that attaches to the blood cells and tissues. The more glucose that is attached, the greater the risk of diabetic complications.

HbA1c measures the amount of glucose attached to the red blood cells The HbA1c gives a good guide to the blood glucose level over the previous 8-10 weeks. It is used as a measure of long-term measure of diabetic control. The usual result in someone without diabetes is 20-42mmol/l (4.0-6.0%).

We believe the best result in diabetes is 42-53mmol/mol (6.0-7.0%). At this term most long term complications can be prevented, whilst at the same time avoiding severe hypos (hypoglycaemia). Below this level there is a higher risk of a bad hypos. Above this level here is an increased risk of complications. Before conception and during pregnancy, slightly lower levels are preferred.

The HbA1c is not the same as the average blood glucose nd is always slightly lower. For example, someone who has a blood glucose ~17mmol/l with have an HbA1c of ~120mmol/mol (13%).

Here is how they relate (and see convertor):


blood glucose range mmol/l HbA1c IFCC-HbA1cmmol/mol
under 7mmol/l (non-diabetic) less than 6 42
mostly under 10 mmol/l 6-7% 42-53
frequently over 10 mmol/l 8-12% 64-108
mostly over 17 mmol/l more than 13% 120



It is useful to record your blood glucose results in a diary, along with carbohydrate intake and insulin dosage, and exercise level. This is a way for you to monitor your control. It will help you choose the right dose of insulin in different situations and reflect on particular results. If you are outside the target range, you will need to adjust your insulin dose.


How to test your blood glucose level

Most people do not know what their actual blood glucose level is at any time purely by the way they feel, except in extreme situations (e.g. very high and low levels). Therefore, if you are aiming to keep your blood glucose level close to normal, you need to monitor it.   Testing


When to test

You only need to test your blood glucose level if the result is to be used to make a decision. Self-monitoring is important to:

Test your blood glucose each day

Testing for Ketones

It is important to test for ketones when (see)

How to test for ketones

Shift work

This is a major challenge; ideally control your diabetes with regular shifts first before changing your shifts. It is much easier now with new insulins or pumps.



If you drive for your living you may have to compromise and have higher glucose levels. This is a decision you should make with your nurse and doctor. Unfortunately if you have high glucose levels they can damage your eyes and kidneys etc. HGV drivers have to give up their HGV licence if they need insulin.