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Warfarin Management (Elevated INR) — UKMLA MCQ

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MediumPharmacologyWarfarin Management (Elevated INR)UKMLAMRCGP AKTPARAMRCEM SBAMRCP Part 1PSA

A clinically well patient takes weekly methotrexate. Baseline creatinine was 80 micromol/L. Two consecutive monitoring sets show creatinine 104 micromol/L, eGFR 60 mL/min/1.73 m², WCC 3.5 ×10^9/L, neutrophils 1.6 ×10^9/L, platelets 140 ×10^9/L, ALT 100 units/L and MCV 105 fL. Which interpretation best matches the stated absolute action thresholds?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — Continue close monitoring because none of the listed values has passed its strict threshold

Explanation lettering: D = shown as A · E = shown as D · A = shown as E

E is correct. The creatinine increase is (104−80)/80 × 100 = exactly 30%, whereas the stated action criterion is more than 30%. The eGFR is exactly 60, not below 60. The WCC, neutrophils and platelets are equal to, rather than below, their listed lower boundaries, while ALT and MCV are equal to, rather than above, their listed upper boundaries. A misreads “more than 30%” as “30% or more.” B misreads “below 60” as “60 or below.” C applies inclusive lower boundaries where the criteria are lower than those values. D similarly treats the upper criteria as inclusive. Although none of the absolute criteria has been crossed, the clustered borderline results and their trends still warrant close monitoring and clinical review.

Reference: NHS SPS, Methotrexate monitoring: https://www.sps.nhs.uk/monitorings/methotrexate-monitoring/