An international study on activated partial thromboplastin time prolongation. Part 2: Interpretative commenting

•Clear evidence-based interpretative comments on laboratory reports may be a great aid for physicians.•Two plasma samples with increased APTT were distributed throughout Europe for coagulation result interpretation.•ICs were evaluated in terms of classification, interpretation, advice, clarity, length and answer to clinical question.•Although most comments contained useful information, up to 36 % of misleading advice was given to physicians.•Several confusing and misleading comments highlights the need for recommendations on elaboration of interpretative comments.