30th April 2024

A 45-year-old man, recently admitted to the ICU following a severe bacterial sepsis, presents with spontaneous skin bruising and bleeding from venipuncture sites.

A 45-year-old man, recently admitted to the ICU following a severe bacterial sepsis, presents with spontaneous skin bruising and bleeding from venipuncture sites. He is febrile and hypotensive despite aggressive fluid resuscitation and antibiotic therapy.

Investigations:

Platelet count: 55 × 10^9/L (150–400)

Prothrombin time (PT): Prolonged

Activated Partial Thromboplastin Time (aPTT): Prolonged

D-dimer: Significantly elevated

Fibrinogen: Decreased

Which additional investigation is most likely to help with the diagnosis?