Which statement correctly describes the relationship among WBC, lymph percent, and CD4 percent?

Which statement correctly describes the relationship among WBC, lymph percent, and CD4 percent?

• A. CD4 cells constitute 5% of total WBC
• B. CD4 cells constitute 25% of total WBC
• C. Lymphocytes constitute 5% of total WBC
• D. WBC total equals 5,500 cells/µL

Answer: (A)

CD4+ T cells are a subset of lymphocytes, which are themselves a portion of the total white blood cells. In a normal differential, neutrophils make up the majority of WBCs, lymphocytes are a smaller yet significant portion, and CD4+ cells are a subset within the lymphocyte pool. Because they are a smaller component of the overall WBC, CD4+ cells usually account for about 5% of the total WBC count. This makes the statement that CD4 cells constitute 5% of total WBC a reasonable description of their relationship to the overall WBC, lymphocyte portion, and CD4 subset. The other statements either imply a larger CD4 fraction than typical, misstate the lymphocyte share, or describe a fixed total WBC count rather than its composition.

CD4+ T cells are a subset of lymphocytes, which are themselves a portion of the total white blood cells. In a normal differential, neutrophils make up the majority of WBCs, lymphocytes are a smaller yet significant portion, and CD4+ cells are a subset within the lymphocyte pool. Because they are a smaller component of the overall WBC, CD4+ cells usually account for about 5% of the total WBC count. This makes the statement that CD4 cells constitute 5% of total WBC a reasonable description of their relationship to the overall WBC, lymphocyte portion, and CD4 subset. The other statements either imply a larger CD4 fraction than typical, misstate the lymphocyte share, or describe a fixed total WBC count rather than its composition.