Blood from a healthy adult individual contains_____________?
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Answer: B. 30% lymphocytes
Explanation
In a healthy adult leukocyte differential, lymphocytes typically account for roughly 20 to 40 percent of cells. Lymphocytes represent the second most common type of circulating white blood cell in normal adult blood. Accurate differential blood counts are essential for diagnosing various infections and hematological disorders. White blood cells protect the human body against invading pathogens, foreign antigens, and malignant cells. A standard leukocyte differential measures the relative percentages of different white blood cell types present. Lymphocytes include specialized B cells, T cells, and natural killer cells involved in adaptive immunity.
Elevated lymphocyte counts often indicate viral infections or chronic inflammatory conditions in clinical practice. Immunocompromised patients may exhibit dangerously low lymphocyte levels, increasing their susceptibility to severe infections. Laboratory technicians evaluate blood smears routinely to assess overall immune system health and function. Neutrophils normally constitute about 55 to 70 percent of circulating white blood cells in healthy adults. Eosinophils account for a very small fraction, typically 1 to 4 percent of total white blood cells. Basophils are the least common granulocytes, normally comprising less than one percent of circulating leukocytes.
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