Blood test for kidney disease
- Creatinine and urea (BUN) in the blood: Blood urea nitrogen and serum creatinine are the most commonly used blood tests to screen for, and monitor renal disease. Creatinine is a product of normal muscle breakdown. Urea is the waste product of breakdown of protein. The level of these substances rises in the blood as kidney function worsens.
- Estimated GFR (eGFR): The laboratory or your physician may calculate an estimated GFR using the information from your blood work. It is important to be aware of your estimated GFR and stage of chronic kidney disease. Your physician uses your stage of kidney disease to recommend additional testing and suggestions on management.
- Electrolyte levels and acid-base balance: Kidney dysfunction causes imbalances in electrolytes, especially potassium, phosphorus, and calcium. High potassium (hyperkalemia) is a particular concern. The acid-base balance of the blood is usually disrupted as well. Decreased production of the active form of vitamin D can cause low levels of calcium in the blood. Inability to excrete phosphorus by failing kidneys causes its levels in the blood to rise. Testicular or ovarian hormone levels may also be abnormal.
- Blood cell counts: Because kidney disease disrupts blood cell production and shortens the survival of red cells, the red blood cell count and hemoglobin may be low (anemia). Some patients may also have iron deficiency due to blood loss in their gastrointestinal system. Other nutritional deficiencies may also impair the production of red cells.