What blood test is essential when initiating anticoagulation treatment?

When initiating anticoagulation treatment, a Complete Blood Count (FBC) is essential because it provides crucial information about the patient's baseline hemoglobin levels, platelet count, and overall blood cell health. This information is critical in identifying any potential risks associated with anticoagulation therapy, such as the risk of bleeding or thrombocytopenia (low platelet levels).

Monitoring these parameters ensures that the healthcare provider can make informed decisions about the appropriateness of starting anticoagulants, adjusting dosages, and ensuring patient safety throughout the treatment. It's also important for detecting any underlying conditions the patient may have that could affect their response to anticoagulation therapy.

Other tests, such as thyroid function tests, serum electrolytes, and lipid profiles, while important in their respective contexts, do not directly assess the readiness or safety of initiating anticoagulation therapy. Thus, a Complete Blood Count is the most pertinent test in this scenario.