A WBC (white blood cell) scan visualizes the distribution of radiolabeled white blood cells in the body to detect active infection or inflammation. Areas where labeled WBCs accumulate indicate sites of bacterial infection, abscess, osteomyelitis, infected prosthetic devices, or inflammatory disease. It helps localize and assess the extent of infection, guide further imaging or intervention, and distinguish infection from noninfectious causes.

A WBC (leukocyte) scan usually requires several hours. Preparing and labeling your white cells takes 1–2 hours, then cells are reinjected and images are taken at multiple times—commonly about 30–60 minutes and again 2–4 hours after injection; some protocols include 20–24‑hour delayed imaging. Expect to be at the imaging center for roughly 3–6 hours overall; exact timing varies by facility.

A white blood cell (WBC) count and differential help detect infections (bacterial, viral, fungal, parasitic), inflammatory conditions (autoimmune diseases, rheumatoid arthritis), allergic reactions, immune deficiencies (including HIV-related changes), bone marrow disorders and hematologic cancers (leukemia, lymphoma), and severe systemic infection/sepsis. Abnormal WBC patterns also suggest tissue damage or recovery after chemotherapy.

A normal white blood cell (WBC) count for adults is about 4,000–11,000 cells per microliter (4.0–11.0 ×10^9/L). It reflects immune system function: higher counts suggest infection, inflammation or stress; lower counts may indicate bone marrow problems, certain infections, autoimmune disease or medication effects. Interpretation varies by age, pregnancy and lab reference ranges, so clinicians assess results with symptoms.

Markedly elevated white blood cell counts are typical in hematologic malignancies—acute leukemias (AML, ALL), chronic leukemias (CML, CLL) and myeloproliferative neoplasms (e.g., polycythemia vera, primary myelofibrosis). Lymphomas (Hodgkin and non‑Hodgkin) can also raise WBC. Advanced solid tumors may cause reactive leukocytosis or a leukemoid reaction, especially lung, renal cell, pancreatic, hepatocellular and colorectal cancers.

A raised white blood cell (WBC) count often suggests infection, especially bacterial, but can also reflect inflammation, stress, tissue injury, steroid use, or blood disorders. A low WBC can occur with viral infections or bone marrow suppression. WBC trends, differential (neutrophils, lymphocytes), clinical signs and additional tests (CRP, cultures, imaging) are needed to confirm and identify the cause.