Clinical Biochemistry Questions

Question 1

Why use laboratory tests?

Answer 1

Diagnosis
Monitoring
Prognosis
Screening

Question 2

What is the reference range?

Answer 2

Mean of all patients +/-2 standard deviations

Question 3

What is NOT used to diagnose diabetes?

Answer 3

Pin prick glucose meter

Question 4

What are the diagnostic tests for diabetes?

Answer 4

Random venous plasma glucose
2hr plasma glucose
Fasting plasma glucose
HbA1c

Question 5

What is a high Random venous plasma glucose ?

Answer 5

> 11.1mmol/L

Question 6

What is a high 2hr plasma glucose?

Answer 6

> 11.1mmol/L

Question 7

What is a high fasting plasma glucose?

Answer 7

> 7mmol/L

Question 8

What is a high HbA1c?

Answer 8

> 48mmol/L

Question 9

How is a diagnosis confirmed in an asymptomatic patient?

Answer 9

Repeat testing on another day

Using another test

Question 10

What is an OGTT?

Answer 10

Oral glucose tolerance test

Question 11

Why does HbA1c tell us a patients control?

Answer 11

Independent of insulin, glucose moves freely into RBC

Question 12

Where is HbA1c located?

Answer 12

Intracellularly

Question 13

When is HbA1c not used?

Answer 13

Young people
Symptoms <2mo
Suspected type 1
Acute illness
Medications that cause a rapid glucose rise (steroids)
Acute pancreatic damage
Pregnancy 
Hematological illness

Question 14

How is diabetes monitored?

Answer 14

Urine - glucose, ketones

Glucose meter measurement

Question 15

A patients pin prick test for glucose comes back high but labs are confirmed hypoglycaemic, why?

Answer 15

Failure to clean the finger on pin prick testing

Question 16

A patient presents with thirst, polyuria, weight loss over 2 mo.
Vomiting, ketones and glucose is elevated.
Patient is dehydrated and tachypnoeic, what is likely to be the cause?

Answer 16

Diabetic ketoacidosis

Question 17

Why is bicarbonate low in DKA?

Answer 17

Bicarbonate is used as a buffer against falling pH

Question 18

What would you suspect carbonates to be in a DKA patient?

Answer 18

Low

Question 19

What would you suspect Potassium to be in a DKA patient?

Answer 19

Depends - have they been vomiting

low if so

Question 20

Why might creatinine be elevated in a patient in DKA?

Answer 20

Elevated - vomiting causes dehydration which means more work for the kidneys

Question 21

What is factitious hypoglycaemia?

Answer 21

High insulin in absense of elevated C-peptide (overuse of insulin)

Question 22

What is the cause of elevated C-peptide?

Answer 22

Insulinoma

Question 23

If a patients insulin is very high but their C-peptide is very low, what is likely to be the cause?

Answer 23

Overuse of insulin

Question 24

What are the major chronic complications of diabetes?

Answer 24

Erectile disfunction
Nephropathy
Foot problems
Micro/macrovascular disease

Question 25

Why is HbA1c used in diabetes?

Answer 25

It tells us about the quality of glycaemic control

Question 26

What factors are measured to assess a diabetic patient?

Answer 26

Glucose
HbA1c
Urine Albumin/creatinine ratio
Lipids

Question 27

What does Urine Albumin/creatinine ratio

tell us?

Answer 27

Renal function - risk for diabetic renal disease

Question 28

A patient has low HbA1c and elevated bilirubin - what is likely to be the cause?

Answer 28

Haemolytic anaemia