T2DM Fasting glucose level - extreme cases

Question

I am working on clinical data analysis and currently dealing with T2DM patients.

When I look at their Fasting glucose level readings, I see that their values range from 0.9 mmol\L to 64 mmol\L

The values are represented in mmol\L and no doubts about it.

What I would like to know is,

1) I know that anything > 7 mmol/L is considered as diabetes but is it possible to go upto this range like 64 mmol\L?

I see this extreme readings (> 20mmol\L) only for around 6% of my dataset.

So, I am here to seek your opinion on whether it is possible or not. The 6% percent is based on >20mmol\L limit that I have chosen.

2) When they are being treated in a diabetes specialist centre, can they still have these extreme values of readings?

3) Am I right to understand that all the below items is used to indicate HbA1c readings? I mean the names have keyword HbA1c but do they all indicate the HbA1c measurement which is used for checking Type 2 diabetes

`Glycated HB, POCT`,
`HbA1c, NGSP/DCCT`,
`HbA1c, POCT`,
`HbA1c, IFCC`,
`Glycated HB` 

4) Which of the below items indicate random glucose? Is all glucose called random glucose

Glucose (120M)

Glucose (60M)

Glucose-6-Phosphate DH, Quantitative

Glucose-6-Phosphate DH Screen

Glucose, CSF

Glucose, Dialysate,

Glucose, Fluid

Glucose, POCT

Glucose, Random Venous. # is it only this one?

Glucose, Urine

Can anyone help?

Answer 1

1) Blood glucose level 64 mmol/L is possible. From a case (a 16-years-old girl with diabetes type 1) report article Severe degree of hyperglycaemia: insights from integrative physiology (OJM, 2002):

The physicians seeking the consultation defined the starting point, the very high blood sugar level of 70 mmol/l (1260 mg/dl).

(^ ^ From the context it's obvious this was a random, not fasting, blood glucose level.)

In diabetes type 2, blood glucose level exceeding 33.3 mmol/L (Anesthesia Progress) or even 50 mmol/L is known as hyperosmolar hyperglycemic state, so levels as high as 64 mmol/L seem to be possible. I believe that by glucose levels, fasting glucose levels are meant.

2) Blood glucose levels >16.7 mmol/L are considered medical emergency (Mayo Clinic), so they should not persist in the records for more than a day after admission to the hospital. The glucose levels 64 mmol/L for several days would be more likely 6.4 mmol/L.

3) HbA1c = glycated Hb (the latter is just a longer term that explains what HbA1c is).

• HbA1c, POCT = Glycated HB, POCT (POCT = Point-of-Care Glycated Hemoglobin Testing)
• HbA1c/NGSP, HbA1c/DCCT and HbA1c/IFCC all show HbA1c, but they present the results in different ways:
  • The old, percentage way of reporting HbA1c values is known as the DCCT (Diabetes Control and Complications Trial) units and the new mmols/mol values are known as the IFCC (International Federation of Clinical Chemistry) units (Diabetes.co.uk).
  • NGSP (National Glycohemoglobin Standardization Program) is another way to present HbA1c values.

So, all the mentioned terms refer to HbA1c test to check for diabetes mellitus, but they use different standards to present results, so they are not the same and they are various calculators available to convert the units. A given hospital/lab usually uses only one of these standards (NGSP, DCCT or IFCC) and they may or may not reveal them in the results, so, they may write down only "HbA1c" or "HbA1c/IFCC," for example. Within a certain hospital/lab, this should not cause confusion, but you need to know the differences when checking this in the literature.

4) Random glucose test shows blood glucose levels at any given random occasion (usually "between the meals"), which means the test is not preceded by any intervention by a patient or doctor, so it does NOT include:

• Fasting blood glucose
• The glucose levels after oral glucose tolerance test (OGTT) after drinking a solution with 75 grams of glucose, which includes Glucose (60M) (blood glucose level 60 minutes after drinking glucose) and Glucose (120M) (120 minutes after)

The only random blood glucose test from your list is Glucose, Random Venous. Only blood glucose test can be "random" (not urine, not CSF, also not HbA1c).

The meaning of other tests, which are usually NOT used for diagnosis of diabetes mellitus:

• Glucose-6-Phosphate DH, Quantitative and Glucose-6-Phosphate DH Screen: these are NOT glucose tests
• Glucose, CSF; CSF = cerebrospinal fluid around the brain and spinal cord
• Glucose, Dialysate; dialysate is a fluid used in dialysis in kidney disease
• Glucose, Fluid or Glucose Body Fluid (GLBF) = glucose levels in various fluid compartments (pleural or peritoneal fluid...) other than blood
• Glucose, POCT = Glucose Point of Care Testing: a repeated test to check for blood glucose levels at the bedside or at home AFTER the diagnosis has been made, so NOT a diagnostic test