Platelet count is not the primary diagnostic test used to monitor the therapy’s effect of warfarin. Platelets are involved in the clotting process, but warfarin specifically works by inhibiting the synthesis of vitamin K-dependent clotting factors, which does not directly involve platelets.

Choice B rationale

The white blood cell count (WBC) is not used to monitor the effect of warfarin therapy. WBC is typically used to monitor for infection or inflammation, not the coagulation status of a patient.

Choice C rationale

Prothrombin time (PT) is the correct answer. Warfarin therapy is monitored using the PT, which is reported as the International Normalized Ratio (INR). Warfarin inhibits the synthesis of vitamin K-dependent clotting factors, which include Factors II, VII, IX, and X, and Proteins C and S. The PT/INR is sensitive to changes in these factors. An elevated INR indicates a higher risk of bleeding, while a lower INR suggests a higher risk of clotting.

Choice D rationale

Activated partial thromboplastin time (aPTT) is not typically used to monitor warfarin therapy. The aPTT test evaluates the intrinsic and common pathways of coagulation, which includes factors XII, XI, IX, VIII, X, V, II (prothrombin), and I (fibrinogen). Warfarin affects the extrinsic pathway and common pathway, not the intrinsic pathway. Therefore, aPTT is not the best test to monitor the effects of warfarin.

Choice A rationale

Airborne precautions are used for diseases that are spread by tiny droplets caused by coughing and sneezing. HIV is not spread through the air, so airborne precautions are not necessary.

Choice B rationale

Standard precautions are used for all patient care. They’re based on the principle that all blood, body fluids, secretions, excretions except sweat, non-intact skin, and mucous membranes may contain transmissible infectious agents. HIV is transmitted by direct or indirect contact with infected blood or body fluids. Therefore, the nurse should plan to implement standard precautions when caring for this patient.

Choice C rationale

Droplet precautions are used for diseases that are spread by large droplets caused by coughing, sneezing, talking, or procedures such as suctioning and bronchoscopy. HIV is not spread through these methods, so droplet precautions are not necessary.

Choice D rationale

Contact precautions are used for diseases that are spread by direct contact with the patient or indirect contact with environmental surfaces or patient care items. HIV is not spread through casual contact, so contact precautions are not necessary.