Clinical Biochemistry - Laboratory Tests in Diabetes

Question 1

If a test was accurate, what does this entail?

Answer 1

A method that produces the correct result

Question 2

If a test was precise, what does this entail?

Answer 2

A method that can provide the
same results consistently

-> therefore results need to be accurate AND precise

Question 3

Which diagnostic tests can be used to diagnose diabetes?

Answer 3

Random venous plasma glucose
Fasting plasma glucose
2hr plasma glucose
HbA2c

Question 4

What result of a random venous plasma glucose if diagnostic for diabetes?

Answer 4

> or equal to 11.1mmol/L

Question 5

What result of a fasting plasma glucose if diagnostic for diabetes?

Answer 5

> or equal to 7.0mmol/L

Question 6

What result of a 2hr plasma glucose if diagnostic for diabetes?

Answer 6

> or equal to 11.1mmol/L

Question 7

What result of a HbA1c is diagnostic for type 2 diabetes?

Answer 7

> or equal to 48mmol/mol

Question 8

What is important to note about these test results in the diagnosis of diabetes?

Answer 8

For a diagnosis of diabetes, these results must be present AS WELL as symptoms.
If asymptomatic two tests are enough to be diagnostic

Question 9

When measuring HbA1c, what is actually being measured?

Answer 9

Glucose moves freely into red blood cells if not taken up by other cells due to lack of insulin so measuring the glucose stuck to RBC’s

Question 10

List some of the times where HbA1c cannot be used in the diagnosis of type 2 diabetes.

Answer 10

-Children and young people
-Suspected type 1 diabetics
-Symptoms <2months
High risk patients who are acutely ill
Patients on meds which cause rapid glucose spikes like steroids
Acute pancreatic damage
Pregnancy

Question 11

What role does urine testing have in diaebets?

Answer 11

Identifies glycosuria and ketonuria

Question 12

13 yr old female with known type 1 diabetes mellitus admitted to A&E because of downiness and vomiting. What is done first?

Answer 12

POCT- point of care finger prick test
Worth sending bloods to labs for more accurate results however, especially if something does not seem right

Question 13

What are low bicarbonate levels indicative of?

Answer 13

Metabolic acidosis

Question 14

Which levels are raised in dehydration?

Answer 14

Urea
Creatine

Question 15

What levels reflect factitious hypoglycaemia?

Answer 15

High insulin levels
Normal C-peptide

-> this is because the insulin has been injected. If it was produced by the body, the C-peptide levels would also be high as when insulin is made in the body, it is initially proinsulin and the C-peptide gets cleaved off to make active insulin

Question 16

A patient has high insulin of 165mU/L (<13)
C-peptide levels are undetectable.
What is the diagnosis?

Answer 16

Too much insulin administered

Question 17

Haemolytic anaemia?

Answer 17

Shortened RBC lifespan so there is increased turnover of RBCs

Question 18

What is tested for signs of diabetic kidney disease?

Answer 18

Urine for albumin leakage