Diagnosis of CRF

Chronic renal failure (CRF) is diagnosed by the observation of a combination of symptoms and elevated blood urea nitrogen (BUN) and creatinine (Cr) levels. The following abnormalities found in the blood may signal CRF:

  • Anemia (low red blood cell count)
  • High level of parathyroid hormone
  • Hypocalcemia (low blood level of calcium)
  • Hyperphosphatemia (high blood level of phosphate)
  • Hyperkalemia (high blood level of potassium)
  • Hyponatremia (low blood level of sodium)
  • Low blood level of bicarbonate
  • Low plasma pH (blood acidity)

Whether renal failure is acute or chronic usually can be distinguished by comparing prior test results (e.g., from the past several months or years). It is difficult to make the distinction without previous test results.

Ultrasound may show that the kidneys are small in size and echogenic (a sign of renal scarring), signs that supports a diagnosis of CRF. For unclear reasons patients with diabetic nephropathy often have preservation of kidney size despite CRF. They do however, typically have increased echogenicity.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 30 Apr 2001

Last Modified: 04 Sep 2015