Best-of-Five Technique for MRCP Part 2: Long, Data-Heavy Questions

MRCP Part 2 questions are long. Many give you a full case, a table of results and sometimes an image, then ask for one best answer from five options that all look reasonable. With 100 questions in three hours, you have an average of 1 minute 48 seconds for each. A consistent method for MRCP Part 2 best of five questions saves time and stops you answering the wrong question. This guide sets one out, with a worked example of the data interpretation that Part 2 rewards.

Exam information checked on 27 October 2026 against the Federation’s Part 2 format page.

What “best of five” really means

The Federation describes each question as having one correct answer and four alternatives that are closely related to it but less correct. In other words, several options may be things a sensible doctor could do. Your job is to choose the one that is best for this patient, at this point, given everything in the stem.

Each correct answer scores one mark and there is no negative marking. Never leave a question blank.

Step 1: read the question line first

Before you read the case, read the final sentence. The Federation lists five things the exam tests: prioritising a diagnostic or problem list, planning investigation, choosing immediate management, choosing long-term management and assessing prognosis. The question line tells you which one you are being asked.

This matters because the same case can have different answers. If the question asks for the most likely diagnosis, you need the condition that explains everything. If it asks for the most appropriate next investigation, you need the test that should come next, which may not be the one that confirms the diagnosis. If it asks for immediate management, safety comes first.

Step 2: read the stem with a purpose

Now read the case, building a short problem list as you go. Note the age, the setting (emergency department, ward or clinic), the time course and anything that makes the patient unwell now. Pay attention to drug histories; prescribing is woven through Part 2, and clinical pharmacology alone carries 18 questions on the current blueprint.

Look for the detail that does not fit the obvious diagnosis. In a long stem, an unexpected finding is rarely there by accident.

Step 3: work the data

Do not just scan the results for flags. Compare them with the reference ranges given, look at trends over time and do the simple calculations. A few are worth practising until they are automatic:

• Anion gap = sodium minus (chloride plus bicarbonate). A raised gap in a metabolic acidosis suggests an added acid, such as lactate, ketones, salicylate or a toxic alcohol, or renal failure.
• Osmolar gap = measured osmolality minus calculated osmolality, where calculated osmolality is (2 × sodium) + glucose + urea. A gap above about 10 suggests an unmeasured osmole, such as ethanol, methanol or ethylene glycol.
• Adjusted calcium = measured calcium + 0.02 × (40 minus albumin in g/L).
• Expected respiratory compensation in a metabolic acidosis (Winter’s formula): expected PaCO₂ in mmHg = (1.5 × bicarbonate) + 8, plus or minus 2. Divide by 7.5 to convert to kPa.
• Serum-ascites albumin gradient = serum albumin minus ascitic albumin. A gradient of 11 g/L or more suggests portal hypertension.

A worked example

Here is a short example of the kind of reasoning involved. A 45-year-old man is brought in drowsy. His results show sodium 138, chloride 100, bicarbonate 10, glucose 6.0 and urea 5.0 (all mmol/L), with a measured osmolality of 320 mOsm/kg. His PaCO₂ is 3.0 kPa.

• Anion gap: 138 minus (100 + 10) = 28. That is raised, so this is a high anion gap metabolic acidosis.
• Calculated osmolality: (2 × 138) + 6 + 5 = 287. Osmolar gap: 320 minus 287 = 33. That is markedly raised.
• Expected PaCO₂: (1.5 × 10) + 8 = 23 mmHg, about 3.1 kPa. His measured 3.0 kPa is within the expected range, so respiratory compensation is appropriate and there is no separate respiratory disorder.

A high anion gap acidosis with a large osmolar gap and a normal glucose should make you think of toxic alcohol ingestion, such as methanol or ethylene glycol. The question might then ask for the most appropriate immediate treatment or the most useful next investigation. Without the calculations, you could easily stop at “metabolic acidosis” and choose a less specific answer.

Step 4: predict, then compare the two closest options

Before you look at the options, decide what you think the answer is. Then read all five. If your prediction is there, check it against the closest alternative. If it is not, you have learned something about the question.

Most marks are won or lost between two options. When you are down to two, ask:

• Timing: is the question about now, or about the long term? A sound long-term treatment is the wrong answer to an immediate management question.
• Sequence: is it asking for the first test, or the definitive one? The most specific test is not always the next step.
• Safety: is the patient unstable? Resuscitation and treatment of a life-threatening problem come before diagnostic work-up.
• Fit: which option explains every abnormal finding in the stem, not just the most striking one?

Step 5: answer, flag and move on

If you are still unsure after a reasonable attempt, choose the best option you have, flag the question and move on. Spending four minutes on one question takes time from two others you might have answered well. Change a flagged answer only when you find something specific that you missed, not on a vague second feeling.

Pacing over three hours

At the exam’s average pace you would reach question 25 after 45 minutes, question 50 after 90 minutes and question 75 after 2 hours 15 minutes. Aim to be slightly ahead of those checkpoints so that you have time at the end for flagged questions. Long data questions and short image questions tend to balance out, so do not panic over a single slow question; check the overall pace at each checkpoint instead.

How to build the skill

Technique improves with timed practice and careful review. Start with untimed blocks while you build the habit of reading the question line first and working the data, then move to timed blocks of 25 and 50 questions, and then full papers. Our 12-week MRCP Part 2 revision plan shows how to fit this into a working week, and our guide to MRCP Part 2 image questions covers the images.

Our MRCP Part 2 course has 4,278 exam-style questions mapped to the current blueprint, plus 400+ image questions and timed mocks in the official two-paper format. See the access options here.

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