Clinical Biochemistry

Question 1

When are laboratory tests used in diagnosis?

Answer 1

Confirmation or rejection of diagnosis

Question 2

Why are laboratory tests used?

Answer 2

• Diagnosis
• Monitoring
• Prognosis
• Screening

Question 3

When are laboratory tests used in monitoring?

Answer 3

Natural history or response to treatment

Question 4

When are laboratory tests used in prognosis?

Answer 4

Prediction of course or outcome of the disease

Question 5

When are laboratory tests used in screening?

Answer 5

Detection of sub-clinical disease

Question 6

What are the stages in laboratory testing?

Answer 6

• Clinical question
• Request form with clinical data
• Patient sampled
• Transit to lab
• Reception and ID
• Analysis
• Quality control
• Collation
• Interpretation
• Reporting
• Biochemical answer

Question 7

Accuracy

Answer 7

Can the method produce the correct result

Question 8

Precision

Answer 8

Can the method produce a consistent answer

Question 9

How are laboratory tests used in the diagnosis of diabetes?

Answer 9

-Random venous plasma glucose >11.1mmol/L
-Fasting plasma glucose >7.0mmol/L
-2 hour plasma glucose >11.1mmol/L in OGTT
-HbA1c >48mmol/mol (Type 2 Diabetes only)
-If asymptomatic, requires confirmation by repeat
testing on another day

Question 10

When should HbA1c not be used to diagnose diabetes?

Answer 10

• Children and young people
• Suspected Type 1 diabetes
• Symptoms <2 months
• High risk patients who are acutely ill
• Patients taking medication that may cause rapid glucose rise (e.g. steroids)
• Acute pancreatic damage
• Pregnancy
• Presence of genetic, haematological or illness-related factors that affect HbA1c and its measurement

Question 11

What biochemistry tests can be carried out in the acute monitoring of diabetes?

Answer 11

• Urines testing for glycosuria or ketonuria

- Glucose meter measurement of capillary blood glucose

Question 12

Factitious hypoglycaemia

Answer 12

High insulin levels in absence of elevated C-peptide concentrations

Question 13

Insulinoma

Answer 13

Elevated C-peptide level indicative of insulin-secreting tumour

Question 14

Give examples of chronic complications of diabetes

Answer 14

Macrovascular disease

• TIA
• Stroke
• Angina
• MI
• Cardiac failure

Microvascular disease

• Diabetic retinopathy
• Nephropathy
• Erectile dysfunction
• Foot problems

Question 15

What biochemical measurements can be taken in the chronic management of diabetes?

Answer 15

• Glucose (self-monitoring of blood glucose)
• HbA1c (Glycaemic control)
• Urine Albumin/creatinine ratio (Diabetic renal disease - Microvascular screening)
• Lipids (Macrovascular screening)

Question 16

What should young people with diabetes have tested annually from the age of 12?

Answer 16

ACR to screen for diabetic kidney disease