What substance should be added to correct a prolonged coagulation test due to plasma factor deficiency?

To correct a prolonged coagulation test resulting from a plasma factor deficiency, the addition of normal plasma is crucial. Normal plasma contains all the necessary coagulation factors in their appropriate concentrations. When a patient has a deficiency of specific clotting factors, the prolonged coagulation time reflects this deficiency, leading to increased bleeding risk.

By introducing normal plasma into the test, the missing factors are provided, allowing the coagulation cascade to function correctly. This effectively restores the balance necessary for normal clot formation, thereby reducing the time it takes for clotting to occur.

Normal saline, activated charcoal, and calcium chloride do not replace the specific coagulation factors that are deficient and therefore would not correct the prolonged coagulation test appropriately. Normal saline may dilute the sample but will not provide the necessary factors. Activated charcoal is not relevant to coagulation at all, as it is used for absorbing toxins in certain medical scenarios. Calcium chloride plays a role in the coagulation process as it is essential for clotting, but it cannot substitute for missing coagulation factors in the plasma. Thus, normal plasma is the optimal solution for addressing the issue effectively.