top of page
Search

Clinical Sciences: 25 Practice MCQs (Biochemistry) for MRCP Part 1

TL;DR

This article explains how biochemistry is tested in MRCP Part 1, highlights the most exam-relevant areas, and shows how to practise MCQs efficiently. It includes high-yield revision points, a worked example MCQ, common traps, and a practical checklist to improve scores with focused study.


Why biochemistry matters in MRCP Part 1

Clinical biochemistry forms a substantial part of the Clinical Sciences syllabus in MRCP Part 1. Questions are rarely about memorising entire pathways; instead, they assess whether candidates can interpret biochemical data in a clinical context. This includes recognising patterns in acid–base balance, electrolyte disturbances, liver function tests, and metabolic disorders.

According to the official MRCP(UK) syllabus published by the Federation of Royal Colleges of Physicians of the United Kingdom (https://www.mrcpuk.org/mrcpuk-examinations/part-1), candidates are expected to apply biochemical principles to common medical presentations rather than recall isolated facts. This is why targeted MCQ practice is essential.

For an overview of the full exam structure, see the MRCP Part 1 overview:https://crackmedicine.com/mrcp-part-1/

Scope of biochemistry questions in MRCP Part 1

Biochemistry questions are integrated across multiple systems. The most frequently tested domains are:

  1. Acid–base physiology – metabolic and respiratory disorders, compensation rules

  2. Electrolytes – sodium, potassium, calcium, and magnesium abnormalities

  3. Liver biochemistry – interpretation of ALT, AST, ALP, GGT, and bilirubin

  4. Metabolism & endocrinology – glucose regulation, lipid metabolism, inborn errors

  5. Nutrition and vitamins – B12, folate, vitamin D, and iron studies

These areas account for the majority of biochemistry-based MCQs in recent diets.


High-yield revision outline (exam-focused)

Use the following numbered list as a rapid framework when revising biochemistry MCQs:

  1. Anion gap metabolic acidosis – DKA, lactic acidosis, uraemia

  2. Compensation formulas – especially Winter’s formula

  3. Hyponatraemia – SIADH vs hypovolaemic vs hypervolaemic causes

  4. Hyperkalaemia – ECG changes and drug-related causes

  5. Liver enzyme patterns – cholestatic vs hepatocellular injury

  6. Bilirubin metabolism – conjugated vs unconjugated jaundice

  7. Glycogen storage diseases – key adult presentations

  8. Urea cycle defects – hyperammonaemia with normal anion gap

  9. Lipid disorders – familial hypercholesterolaemia patterns

  10. Vitamin deficiencies – biochemical clues with clinical correlation

If you are practising questions regularly, many of these themes will repeat in different disguises.


The 5 most tested biochemistry subtopics

1. Acid–base disorders

Candidates must identify the primary abnormality before looking at compensation. Mixed disorders are common. Always calculate the anion gap when bicarbonate is low.

2. Sodium disorders

Hyponatraemia questions often include serum osmolality and volume status. The trap is diagnosing SIADH without excluding hypovolaemia or diuretic use.

3. Potassium abnormalities

Expect questions on medication effects (ACE inhibitors, spironolactone), ECG changes, and pseudohyperkalaemia due to haemolysis.

4. Liver biochemistry

Examiners prefer patterns over single values. Very high ALT suggests acute hepatocellular injury; disproportionately raised ALP suggests cholestasis.

5. Vitamins and nutrition

High-yield because deficiencies link biochemistry with neurology and haematology. B12 deficiency causes neurological signs; folate deficiency does not.


Mini-MCQ with explanation

Question A 58-year-old man presents with vomiting and confusion. Arterial blood gas shows:

  • pH 7.29

  • HCO₃⁻ 13 mmol/L

  • PaCO₂ 27 mmHg

  • Na⁺ 140 mmol/L, Cl⁻ 101 mmol/L

What is the most likely diagnosis?

Answer High anion gap metabolic acidosis with appropriate respiratory compensation.

Explanation Anion gap = 140 − (101 + 13) = 26 (raised).Low pH and low bicarbonate indicate metabolic acidosis. The low PaCO₂ reflects respiratory compensation. In MRCP Part 1, this pattern commonly points towards lactic acidosis, diabetic ketoacidosis, or renal failure, depending on the stem.


MRCP Part 1 candidates studying clinical biochemistry together

Common pitfalls (exam traps)

  • Misidentifying compensation as the primary disorder

  • Ignoring volume status in hyponatraemia

  • Over-interpreting isolated lab values

  • Revising rare metabolic pathways without clinical focus

  • Forgetting drug-induced biochemical abnormalities

Avoiding these mistakes alone can significantly improve scores.


Practical study-tip checklist

Use this checklist during your revision cycle:

  • ☐ Practise biochemistry MCQs daily, even during clinical blocks

  • ☐ Always review why incorrect options are wrong

  • ☐ Keep a one-page acid–base summary sheet

  • ☐ Use short, focused resources rather than long textbooks

  • ☐ Test progress regularly with timed papers

You can practise systematically using the Crack Medicine Question Bank:https://crackmedicine.com/qbank/

To benchmark performance under exam conditions, use full-length mock tests:https://crackmedicine.com/mock-tests/


How this article fits your MRCP Part 1 preparation

This post supports the Clinical Sciences component of the MRCP Part 1 hub. For a structured timetable, see the related article Study Plan for MRCP Part 1:https://crackmedicine.com/blog/mrcp-study-plan/

For concept reinforcement, concise video explanations are available in the Lectures section:https://crackmedicine.com/lectures/


FAQs

Is biochemistry heavily tested in MRCP Part 1?

Yes. It is a core component of Clinical Sciences and frequently integrated with renal, endocrine, and liver questions.

Do I need to memorise full biochemical pathways?

No. Focus on clinically relevant steps, patterns, and consequences rather than entire pathways.

Are calculations required in the exam?

Only simple calculations such as anion gap or corrected calcium are expected.

What is the best way to improve biochemistry scores?

Regular MCQ practice with detailed post-question analysis is the most effective approach.


Ready to start?

Consolidate this framework by attempting targeted biochemistry sets in the Free MRCP MCQs and validating progress with a mock test under exam conditions.


Sources

 
 
 

Comments

bottom of page