Elevation is seen with infection, leukemia, hemorrhage and malignancy.

• A. Leukocyte
• B. Hematocrit
• C. Platelet count
• D. Hemoglobin

Answer: (A)

White blood cell count goes up when the body is fighting infection or when there is abnormal bone marrow activity as seen in leukemia. It can also rise after tissue injury or hemorrhage because inflammatory signals recruit leukocytes to damaged areas, and certain cancers can trigger a reactive increase in white cells. This makes leukocytes the most consistent marker for those conditions.

Hematocrit and hemoglobin reflect red blood cell mass and tend to rise with dehydration or polycythemia, not specifically with infection or leukemia. Platelet counts can vary with inflammation or bleeding—sometimes increasing briefly with infection, but they are not as consistently elevated in these scenarios and can drop after substantial hemorrhage.