A. (incorrect) Clients who are overhydrated or have fluid volume excess would experience dilutional values of sodium (135-145 mEq/L) and red blood cells (44% to 52%). The levels would be lower than normal, not higher.
B. (incorrect) Anemia is a low red blood cell count for a variety of reasons.
C. (correct) Dehydration results in concentrated serum that causes lab values to increase because the blood has normal constituents but not enough volume to dilute the values to within normal range or possibly lower.
D. (incorrect) In renal failure, the kidneys cannot excrete, and this results in too much fluid in the body.
TEST-TAKING HINT: The test taker must decide first if the values are high or low and then determine what is happening with body fluids in each process. Overhydration and renal failure result in the same fluid shift, so these two options (A and D) could be excluded.