Which type of specimen is primarily analyzed for the Complete Blood Count (CBC)?

The Complete Blood Count (CBC) is a fundamental laboratory test that provides essential information about the cellular components of blood, including red blood cells, white blood cells, and platelets. This test typically uses a blood specimen because these components are directly suspended in blood and are crucial for evaluating a patient's overall health. The CBC assesses critical indices such as hemoglobin levels, hematocrit, and various white blood cell counts, which are vital for diagnosing conditions like anemia, infections, and other hematologic disorders.

Other specimen types like urine, saliva, and feces do not provide the necessary cellular information required for a complete blood count, as they contain different biological components that are not relevant to the parameters that the CBC measures. Therefore, blood is the only correct and relevant choice for this analysis, as it is specifically tailored to evaluate these hematological parameters.