A differential count (DC) test is a type of complete blood count (CBC) that examines the different types of white blood cells (WBCs) present in a blood sample. It counts the percentage of each type of WBC, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils. A differential count is often performed to diagnose infections, inflammatory conditions, autoimmune disorders, and certain types of cancer. It can also help monitor treatment effectiveness for these conditions. The normal range for each type of WBC may vary slightly depending on the lab performing the test and the age and gender of the patient. An abnormal differential count may indicate a specific underlying medical condition and may require further testing or treatment.