Which blood parameter is commonly used to estimate radiation dose in exposed individuals?

Which blood parameter is commonly used to estimate radiation dose in exposed individuals?

• A. White blood cell count
• B. Lymphocytes count
• C. Platelet count
• D. Hematocrit

Answer: (B)

Lymphocytes are the most radiosensitive circulating cells, so their numbers fall quickly after radiation exposure. This rapid depletion creates a direct, early link between absorbed dose and blood values, making lymphocyte count a practical and timely way to estimate radiation dose in exposed people. In the first day or two after exposure, the decrease in lymphocytes correlates with dose, helping with rapid triage and initial assessment. Other parameters are less reliable early indicators: white blood cell count includes cells with more variable responses, platelets decline later as bone marrow suppression develops, and hematocrit is affected by hydration and other factors rather than radiation dose. While more precise tests like cytogenetic analyses exist, measuring lymphocyte count provides the quickest, readily available estimate of dose.

Lymphocytes are the most radiosensitive circulating cells, so their numbers fall quickly after radiation exposure. This rapid depletion creates a direct, early link between absorbed dose and blood values, making lymphocyte count a practical and timely way to estimate radiation dose in exposed people. In the first day or two after exposure, the decrease in lymphocytes correlates with dose, helping with rapid triage and initial assessment. Other parameters are less reliable early indicators: white blood cell count includes cells with more variable responses, platelets decline later as bone marrow suppression develops, and hematocrit is affected by hydration and other factors rather than radiation dose. While more precise tests like cytogenetic analyses exist, measuring lymphocyte count provides the quickest, readily available estimate of dose.