PLAB 1 Diabetes Questions: 10 Free Practice MCQs

Ten PLAB 1-style diabetes questions with the answer and the reasoning behind it. They come from the UK.med bank, which has 55 diabetes questions and many more across every topic.

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1. 1 / 10

   A 31-year-old primigravida at 24 weeks' gestation with a BMI of 31 is screened for gestational diabetes mellitus (GDM) using a 75g oral glucose tolerance test (OGTT). Her results reveal a fasting plasma glucose of 5.8 mmol/L and a 2-hour plasma glucose of 8.2 mmol/L. She is otherwise well and has no other co-morbidities.

   What is the most appropriate initial management step according to NICE guidelines?

   • A. Immediately initiate oral Metformin 500mg once daily
   • B. Immediately initiate subcutaneous rapid-acting insulin therapy
   • C. Reassure the patient that these values are normal and repeat the OGTT at 28 weeks
   • D. Offer a trial of diet and exercise for up to 2 weeks, and advise self-monitoring of blood glucose
   Show answer

   Answer: D. Offer a trial of diet and exercise for up to 2 weeks, and advise self-monitoring of blood glucose

   Why: NICE guideline NG3 defines the diagnostic thresholds for gestational diabetes as a fasting plasma glucose of >= 5.6 mmol/L or a 2-hour plasma glucose of >= 7.8 mmol/L. For women with a fasting glucose < 7.0 mmol/L, initial management is lifestyle modification (diet and exercise) for 1-2 weeks. If glucose targets are not met, Metformin is added. If Metformin is contraindicated, untolerated, or insufficient, insulin is added. If fasting glucose is >= 7.0 mmol/L at diagnosis, insulin should be offered immediately.

   • A. Metformin is indicated if blood glucose targets are not met within 1-2 weeks of diet and exercise alteration, or immediately if fasting glucose is >= 7.0 mmol/L, not as the first step for fasting glucose < 7.0 mmol/L.
   • B. Immediate insulin (with or without Metformin) is indicated if the fasting glucose at diagnosis is >= 7.0 mmol/L, or if there is severe macrosomia or polyhydramnios, which is not present here.
   • C. Under NICE guidelines, GDM is diagnosed if fasting glucose is >= 5.6 mmol/L or 2-hour glucose is >= 7.8 mmol/L. Both of her values are elevated, confirming gestational diabetes.

   Sources: NICE NG3

2. 2 / 10

   A 59-year-old man with type 2 diabetes has an HbA1c of 62 mmol/mol, above his agreed target, despite taking his maximum tolerated metformin dose and completing structured diabetes education. He has no heart failure, CKD or established cardiovascular disease. A GLP-1 receptor agonist is contraindicated for him, and a DPP-4 inhibitor is appropriate.

   Which additional glucose-lowering medicine should be offered next?

   • A. Add a DPP-4 inhibitor alongside the maximum tolerated metformin dose
   • B. Increase metformin beyond his maximum tolerated dose despite persistent gastrointestinal adverse effects and prior dose-limiting diarrhoea
   • C. Add a sulfonylurea before considering a DPP-4 inhibitor
   • D. Stop metformin and increase lisinopril to improve glycaemia
   Show answer

   Answer: A. Add a DPP-4 inhibitor alongside the maximum tolerated metformin dose

   Why: His glycaemia remains above target despite the maximum tolerated metformin dose and structured education. NICE NG28 recommends additional treatment, and its current pathway supports a DPP-4 inhibitor when GLP-1 receptor agonist treatment is contraindicated or unsuitable. A sulfonylurea is a later alternative if DPP-4 treatment cannot be used or does not work.

   • B. His current dose is already the maximum tolerated dose, so escalation would not be appropriate.
   • C. A sulfonylurea is considered if a DPP-4 inhibitor is contraindicated, not tolerated or ineffective, rather than before it.
   • D. Lisinopril does not lower glucose, and there is no reason in the vignette to stop tolerated metformin.

   Sources: NICE NG28: Type 2 diabetes in adults, updated February 2026

3. 3 / 10

   A 52-year-old woman is diagnosed with type 2 diabetes mellitus after her HbA1c is found to be 52 mmol/mol on two occasions. Lifestyle and dietary modifications for 3 months have failed to improve her glycaemic control, and she has no other health conditions.

   What is the first-line pharmacological treatment, and what is the target HbA1c level she should aim for on monotherapy?

   • A. Metformin; target HbA1c 48 mmol/mol
   • B. Gliclazide; target HbA1c 53 mmol/mol
   • C. Empagliflozin; target HbA1c 48 mmol/mol
   • D. Pioglitazone; target HbA1c 58 mmol/mol
   Show answer

   Answer: A. Metformin; target HbA1c 48 mmol/mol

   Why: NICE guideline NG28 states that standard release Metformin should be offered first-line for type 2 diabetes. The dose should be titrated slowly over several weeks to minimize gastrointestinal side effects. For patients managed on lifestyle/diet or a single non-hypoglycaemic drug (like Metformin), the target HbA1c is 48 mmol/mol (6.5%). If treatment is intensified to dual therapy, the target rises to 53 mmol/mol (7.0%).

   • B. Gliclazide (sulfonylurea) is not first-line due to risks of hypoglycaemia and weight gain, and target HbA1c on monotherapy is 48, not 53.
   • C. While SGLT2 inhibitors like Empagliflozin are used early, Metformin remains the standard first-line monotherapy unless the patient has established cardiovascular disease or high risk.
   • D. Pioglitazone is not first-line and carries risks of fluid retention and bladder cancer. The target is 48 mmol/mol.

   Sources: NICE NG28

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5. 4 / 10

   A 12-year-old boy is diagnosed with type 1 diabetes mellitus. He presents to the clinic with a 2-week history of polyuria, polydipsia, and weight loss. His random blood glucose level is 22 mmol/L.

   What is the underlying mechanism for this patient's condition?

   • A. Autoimmune destruction of pancreatic beta cells
   • B. Genetic mutation leading to insulin resistance
   • C. Pancreatic alpha cell dysfunction
   • D. Hormonal imbalance leading to hyperglycaemia
   Show answer

   Answer: A. Autoimmune destruction of pancreatic beta cells

   Why: Type 1 diabetes mellitus is caused by autoimmune destruction of pancreatic beta cells, leading to a deficiency of insulin production. This results in hyperglycaemia and the symptoms presented by the patient.

   • B. This is incorrect as the patient has type 1 diabetes mellitus, which is not caused by genetic mutation leading to insulin resistance.
   • C. This is incorrect as the patient has type 1 diabetes mellitus, which is not caused by pancreatic alpha cell dysfunction.
   • D. This is incorrect as the patient has type 1 diabetes mellitus, which is not caused by hormonal imbalance leading to hyperglycaemia.

   Sources: NICE Guideline NG28

6. 5 / 10

   A 62-year-old man with type 2 diabetes remains above his agreed HbA1c target despite maximum tolerated metformin and appropriate initial add-on treatment. A GLP-1 receptor agonist is contraindicated, and a DPP-4 inhibitor has been tried but was ineffective. He has no heart failure, CKD or established cardiovascular disease.

   Which additional treatment is a NICE-supported option now?

   • A. Increase metformin beyond the maximum tolerated dose
   • B. Refer every patient at this stage directly to hospital endocrinology
   • C. Offer a sulfonylurea as one of the next treatment options
   • D. Stop lisinopril because ACE inhibitors worsen glucose control
   Show answer

   Answer: C. Offer a sulfonylurea as one of the next treatment options

   Why: His HbA1c remains above target despite metformin, and GLP-1 receptor agonist treatment is contraindicated while a DPP-4 inhibitor has not worked. Current NICE NG28 lists a sulfonylurea, pioglitazone or insulin-based treatment as options in this situation. Choice should reflect hypoglycaemia risk, comorbidities and the patient's preferences.

   • A. A dose above his maximum tolerated amount risks adverse effects and is not the next step.
   • B. NICE supports further treatment choices in primary care when clinically appropriate; automatic referral is not required by these facts.
   • D. Lisinopril is not stopped for this reason and does not explain inadequate glycaemic control.

   Sources: NICE NG28: Type 2 diabetes in adults, updated February 2026

7. 6 / 10

   A 21-year-old university student with a 10-year history of type 1 diabetes mellitus is reviewed in primary care. He is on a basal-bolus insulin regimen and monitors his glucose using a continuous glucose monitor (CGM). His current HbA1c is 56 mmol/mol.

   What is the recommended target HbA1c for adults with type 1 diabetes according to NICE guidelines?

   • A. 53 mmol/mol (7.0%) or lower
   • B. 58 mmol/mol (7.5%) or lower
   • C. 42 mmol/mol (6.0%) or lower
   • D. 48 mmol/mol (6.5%) or lower
   Show answer

   Answer: D. 48 mmol/mol (6.5%) or lower

   Why: NICE guideline NG17 states that the target HbA1c for adults with type 1 diabetes is 48 mmol/mol (6.5%) to reduce vascular complications. Clinicians should support patients to achieve this target through structured education (e.g. DAFNE), multiple daily insulin injections (basal-bolus) or pump therapy, and real-time continuous glucose monitoring (rtCGM), which is now recommended for all adults with type 1 diabetes.

   • A. 53 mmol/mol is the target for type 2 diabetes on dual therapy, not the tighter target of 48 mmol/mol for type 1 diabetes.
   • B. 58 mmol/mol is considered suboptimal control; tighter control (48 mmol/mol) is recommended to prevent nephropathy and retinopathy.
   • C. A target of 42 mmol/mol is too low and carries an unacceptably high risk of severe hypoglycaemia in type 1 diabetes.

   Sources: NICE NG17

8. 7 / 10

   A 60-year-old woman with type 2 diabetes takes metformin 500 mg twice daily. Attempts to increase it caused persistent diarrhoea. HbA1c remains 63 mmol/mol on repeat testing despite adherence and lifestyle support. She has no cardiovascular disease, heart failure or kidney disease, and a DPP-4 inhibitor is suitable.

   Which medicine should be offered next to improve glycaemic control?

   • A. Increase metformin to 1 g twice daily despite persistent intolerance
   • B. Add a sulfonylurea before trying a DPP-4 inhibitor
   • C. Increase lisinopril because it directly lowers HbA1c
   • D. Add a DPP-4 inhibitor to the tolerated metformin dose
   Show answer

   Answer: D. Add a DPP-4 inhibitor to the tolerated metformin dose

   Why: His HbA1c remains above the agreed target despite adherence and lifestyle support, and 500 mg twice daily is his maximum tolerated metformin dose. Under current NICE NG28 recommendations for people without a relevant comorbidity, offer a DPP-4 inhibitor as further treatment. A sulfonylurea is an alternative if a DPP-4 inhibitor is contraindicated, not tolerated or ineffective.

   • A. He cannot tolerate a higher metformin dose, so increasing it is inappropriate.
   • B. For a person without relevant comorbidity who needs further treatment, current NICE guidance offers a DPP-4 inhibitor first.
   • C. Lisinopril treats hypertension and does not provide glucose-lowering treatment.

   Sources: NICE NG28: Type 2 diabetes in adults, updated February 2026

9. 8 / 10

   A 44-year-old woman with no diagnosed cardiovascular disease attends an NHS Health Check. She smokes 10 cigarettes daily, has a raised non-fasting cholesterol result and a clinic blood pressure of 146/92 mmHg.

   What should the cardiovascular risk assessment help the clinician and patient do?

   • A. Confirm a diagnosis of coronary artery disease from the cholesterol result
   • B. Replace the separate NHS breast and bowel screening programmes
   • C. Estimate future cardiovascular risk and guide prevention choices
   • D. Choose a specific antihypertensive drug without confirming persistent hypertension
   Show answer

   Answer: C. Estimate future cardiovascular risk and guide prevention choices

   Why: The NHS Health Check assesses cardiovascular risk in eligible adults without known cardiovascular disease and helps guide prevention. Risk factors such as smoking, blood pressure and cholesterol contribute to the estimate, which supports shared decisions about lifestyle and treatment. A risk score is not itself a diagnosis of coronary disease.

   • A. A raised cholesterol result alone does not diagnose coronary artery disease; risk assessment estimates future risk.
   • B. The Health Check does not replace age- and risk-based cancer screening programmes.
   • D. A single clinic reading does not by itself settle the diagnosis or determine the full treatment plan.

   Sources: NHS Health Check programme, Department of Health and Social Care, 2022

10. 9 / 10

    A 62-year-old man with type 2 diabetes takes metformin 500 mg twice daily without adverse effects. His HbA1c has risen to 64 mmol/mol despite taking it regularly; his eGFR is 85 mL/min/1.73 m². He has already received dietary and physical-activity advice.

    Which is the most appropriate next step for his glycaemic management?

    • A. Add a sulfonylurea immediately without reviewing his current treatment
    • B. Refer to secondary care before making any change to treatment
    • C. Make no change because 64 mmol/mol is an acceptable HbA1c target for all adults taking metformin, even when their agreed target is lower
    • D. Reinforce healthy-living and adherence advice, increase metformin towards the maximum tolerated dose, and recheck HbA1c in 3 months
    Show answer

    Answer: D. Reinforce healthy-living and adherence advice, increase metformin towards the maximum tolerated dose, and recheck HbA1c in 3 months

    Why: His HbA1c is above the usual target and he is taking a low dose of metformin with preserved renal function and no adverse effects. Reinforce healthy-living and adherence advice and optimise the existing medicine before deciding whether another glucose-lowering drug is needed. NICE recommends checking HbA1c every 3 to 6 months until it is stable on unchanged treatment.

    • A. A sulfonylurea is not the first adjustment to make when a tolerated metformin dose has not yet been optimised.
    • B. An HbA1c above target on a low, tolerated metformin dose can usually be addressed in primary care.
    • C. Targets should be individualised, but 64 mmol/mol is above the usual target for someone on metformin without hypoglycaemia risk.

    Sources: NICE NG28: Type 2 diabetes in adults, recommendations 1.5.1, 1.5.7 and 1.5.8, current guidance

11. 10 / 10

    A 62-year-old man with type 2 diabetes has an HbA1c of 64 mmol/mol while taking metformin. At his review, he says he has never attended a structured diabetes education programme and asks for help with meal planning, medicines and self-management.

    What is the most appropriate response to his request for day-to-day self-management support?

    • A. Start insulin immediately without discussing his current treatment or preferences
    • B. Tell him that education is unnecessary once a person is taking diabetes medicine
    • C. Offer a suitable structured diabetes education programme and review his HbA1c and medicines separately
    • D. Refer to a specialist only because every HbA1c above 58 mmol/mol requires hospital care
    Show answer

    Answer: C. Offer a suitable structured diabetes education programme and review his HbA1c and medicines separately

    Why: NICE recommends offering structured education to adults with type 2 diabetes and reviewing or reinforcing it regularly. This directly addresses his request for support with self-management. His HbA1c of 64 mmol/mol is also above the usual target, so the GP should separately review adherence, current medicines and whether treatment needs intensifying.

    • A. An insulin decision requires an individual treatment review and does not answer his request for structured self-management education.
    • B. NICE recommends structured education as an integral part of type 2 diabetes care, with reinforcement and review.
    • D. An HbA1c above target does not automatically require hospital referral, and structured education can be offered through local services.

    Sources: NICE NG28: Type 2 diabetes in adults, recommendations 1.2.1 and 1.5.8, current guidance

Exam-style questions written by MedHub for practice. They are not official exam questions.