Tuberculosis (TB): Given the symptoms of unintentional weight loss and drenching night sweats, TB is a strong consideration, especially if the patient has been exposed to TB or has risk factors such as immunocompromised status. A normal CBC does not rule out TB, as it can present with non-specific or normal laboratory findings early in the disease.

Lymphoma: Although the CBC is normal, lymphoma can present with systemic symptoms like weight loss and night sweats (B symptoms) before abnormalities are detected in the blood counts. Further imaging and biopsy may be necessary for diagnosis.
Chronic Infections (e.g., Endocarditis, Osteomyelitis): These infections can cause prolonged fever, night sweats, and weight loss. A normal CBC does not exclude these diagnoses, as they can have variable effects on blood cell counts.
Chronic Malignancies (e.g., Solid Tumors): Certain cancers, especially those involving the lung, pancreas, or stomach, can present with weight loss and night sweats due to tumor effects or paraneoplastic syndromes.

HIV/AIDS: This condition can present with weight loss, night sweats, and a normal CBC, especially in the early stages. It's crucial to consider HIV testing due to the significant implications for treatment and prognosis.
Hyperthyroidism: Although less common, hyperthyroidism can cause weight loss and night sweats. It's essential to check thyroid function tests to rule out this condition.

Sarcoidosis: This autoimmune disease can cause systemic symptoms, including weight loss and night sweats, but it is less common than other diagnoses listed here.
Pheochromocytoma: A rare tumor of the adrenal gland that can cause night sweats among other symptoms, though weight loss is less commonly associated with this condition.
Whipple's Disease: A rare, systemic bacterial infection that can cause weight loss, night sweats, and other systemic symptoms, often with a normal CBC.