The nurse is caring for a male patient diagnosed with a Pulmonary Embolism (PE) who has been receiving a heparin IV infusion for 12 hours. Which of the following labs would require the nurse to titrate the heparin drip down?

Hemoglobin 20 g/dL (reference range 13.5-18 g/dL)

Prothrombin time (PT) 10 seconds (reference range 12-15 seconds)

Activated Partial thromboplastin time (aPTT) 89 seconds (reference range 52.5-87.5 seconds)

Platelets 455,000/mm3 (reference range 150,000-400,000/mm3)