The nurse cares for a client who is pale and frequently reports fatigue, weakness, and dizziness. Which serum laboratory test result is the nurse's priority for planning care?

The client's hemoglobin level and sodium level are low; however, the nurse uses the hemoglobin results to plan care because the client's clinical indicators are consistent with anemia. The client is pale because the serum hemoglobin is low; thus, the client's tissues are perfused with blood that has a low oxygen-carrying capacity. The client is weak and dizzy because the blood does not carry enough oxygen to meet tissue oxygen demands. The normal sodium level is 135 to 145 mEq/L (135 to 145 mmol/L). Although a client who is hyponatremic can also feel weak and dizzy, a hyponatremic client is unlikely to be pale. The hematocrit and the potassium levels are within normal limits.