Debrief

Primary hemostasis is coordinated vessel response, platelet adhesion, activation, secretion, aggregation, and a temporary plug. Platelet count and smear assess foundational quantity and morphology evidence, while LTA provides a selected functional pattern under defined conditions. A normal count does not exclude a qualitative platelet or VWF-mediated problem. A reduced ristocetin response directs the differential but does not establish a VWD subtype.

Mucocutaneous bleeding and an abnormal ISTH-BAT score add phenotype information, but neither measures VWF concentration or subtype. VWD diagnosis requires VWF antigen, platelet-dependent VWF activity, and factor VIII activity. The initial plug still needs fibrin reinforcement through secondary hemostasis, which this platelet-function workup does not assess. This boundary prevents treating a platelet-focused result as a complete hemostasis assessment.

Use local policy for analyzer intervals, smear-review triggers, automated count QC, citrate correction-factor validation, LTA reagent and software details, turnaround time, and critical-value definitions. Reassess the method when the analyzer, reagent, LTA panel, reference interval, procedure, or applicable platelet-function guidance changes. Document what the method measured, what the pattern supports, and what evidence is still required.