Medscape is available in 5 Language Editions – Choose your Edition here.


Uremia Workup

  • Author: A Brent Alper, Jr, MD, MPH; Chief Editor: Vecihi Batuman, MD, FACP, FASN  more...
Updated: Feb 05, 2016

Approach Considerations

The diagnosis of renal failure is based primarily on an abnormal glomerular filtration rate (GFR) or abnormal creatinine clearance, which is usually evident due to an elevated serum creatinine level. GFR determination can be accomplished by 24-hour urine collection for creatinine clearance, although this is often cumbersome and inaccurate due to improper collection.

It is very important to determine if the kidney failure is acute or chronic, as acute kidney injury likely is reversible if treated properly. Review of the patient's history and of previous laboratory values can be very helpful in this regard.

Other blood studies to consider for abnormalities prevalent with clinical uremia include the following:

  • Hemoglobin
  • Calcium
  • Phosphate
  • Parathyroid hormone
  • Albumin
  • Potassium
  • Bicarbonate

Urinalysis with microscopic examination should be performed on all patients to evaluate for the presence of protein, cellular casts, oval fat bodies, ketones, hemoglobin, and myoglobin, and to assess pH.

Isotope clearance

The assessment of nuclear medicine radioisotope (iothalamate) clearance is the criterion standard for measuring GFR. However, this test is time consuming and is more expensive than estimating GFR using either the Modification of Diet in Renal Disease (MDRD) formula or the Cockcroft-Gault formula.

Anemia workup

In premenopausal females and prepubertal patients, begin the workup for anemia when the hemoglobin level is less than 11 g/dL or the hematocrit value is less than 33%. In men and postmenopausal women, begin the workup when the hemoglobin level is less than 12 g/dL or the hematocrit value is less than 37%.


Glomerular Filtration Rate

All patients with an abnormal creatinine clearance should have their GFR estimated using one of several formulas that employ easily obtainable values, such as the MDRD or Cockcroft-Gault formula. Both formulas have been shown to provide similar values within a wide range of patient ages and to be accurate in patients with renal insufficiency, regardless of race or sex.


Staging is determined by the GFR (creatinine clearance). Currently, the National Kidney Foundation no longer recognizes the terms chronic renal insufficiency (CRI) or chronic kidney disease (CKD), but rather it recognizes the 5 stages of CKD based on the estimated GFR (eGFR), as calculated by the MDRD formula. These stages are as follows:

  • Stage 1 - Kidney damage with normal GFR, 90 mL/min or greater
  • Stage 2 - Kidney damage with a mild decrease in GFR, 60-89 mL/min
  • Stage 3 - Kidney damage with a moderate decrease in GFR, 30-59 mL/min
  • Stage 4 - Kidney damage with a severe decrease in GFR, 15-29 mL/min
  • Stage 5 - End-stage renal disease, GFR less than 15 mL/min or patient on dialysis


A renal ultrasonographic study is indicated to evaluate for hydronephrosis or obstruction. Hydronephrosis can occur with ureteral or bladder obstruction, retroperitoneal fibrosis, massive abdominal tumors due to cervical or prostate cancers, or other structural abnormalities.

Renal ultrasonography is also performed to determine the size and shape of the kidneys. Large kidneys are associated with diseases such as early diabetic nephropathy, multiple myeloma, polycystic kidney disease, and human immunodeficiency virus (HIV)–associated glomerulonephritis. Small kidneys usually indicate chronic, irreversible damage from diseases such as hypertensive nephrosclerosis, ischemic nephropathy, or any other long-standing kidney disease.


CT Scanning and MRI

Consider a brain computed tomography (CT) scan in the event of a significant change in the patient’s mental status, especially if the change occurs after a fall or in association with mild trauma. Spontaneous subdural hematomas occur in patients with uremia, particularly if the BUN level is greater than 150-200 mg/dL.

CT scanning of the abdomen may be indicated to rule out retroperitoneal fibrosis, pelvic masses, lymphadenopathy, or lymphoma if bilateral hydronephrosis is found on ultrasonographic images and no obvious etiology is present (eg, stone, bladder mass, ureteral mass).

Magnetic resonance imaging (MRI) arteriograms can be used to assess the kidneys for renal artery stenosis, acute arterial thrombosis, or aortic dissection involving the aorta and renal arteries. It is important to consider renal artery stenosis in the differential diagnosis because it is one cause of renal failure that is potentially reversible by angioplasty or bypass surgery of the affected renal artery.



A renal biopsy is necessary to make an accurate diagnosis of acute kidney injury (AKI) or chronic kidney disease (CKD). However, if the renal failure has been slowly progressive and the kidneys are small, renal biopsy results are of little benefit. In the setting of uremia, performing a renal biopsy in a patient with small kidneys may be dangerous because of comorbid disease and the increased risk of bleeding.

In the setting of rapidly progressive renal failure or AKI of unknown etiology, a renal biopsy is indicated to determine whether potentially reversible or treatable renal disorders are present.


Histologic findings vary depending on the underlying etiology. However, in the setting of late-stage CKD and uremia in which renal function has deteriorated over a prolonged period and the kidneys are relatively small, renal biopsy results may show significant glomerulosclerosis and obsolescent glomeruli (completely scarred and sclerosed) with significant interstitial fibrosis. These findings are nonspecific and do not aid in determining the underlying cause of renal failure.

Contributor Information and Disclosures

A Brent Alper, Jr, MD, MPH Associate Professor of Medicine, Section of Nephrology and Hypertension, Department of Medicine, Tulane University School of Medicine

A Brent Alper, Jr, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Society of Hypertension, American Society of Nephrology, National Kidney Foundation, Phi Beta Kappa

Disclosure: Nothing to disclose.


Bessie A Young, MD, MPH Associate Professor of Medicine, Division of Nephrology, University of Washington School of Medicine; Core Investigator, Seattle Epidemiologic Research and Information Center

Bessie A Young, MD, MPH is a member of the following medical societies: American College of Physicians, American Diabetes Association, International Society of Nephrology, National Kidney Foundation, American Society of Nephrology

Disclosure: Nothing to disclose.

Rajesh G Shenava, MD Former Assistant Professor of Medicine, Section of Nephrology and Hypertension, Department of Internal Medicine, Louisiana State University School of Medicine in New Orleans

Rajesh G Shenava, MD is a member of the following medical societies: American College of Physicians, American Society of Nephrology, National Kidney Foundation, Renal Physicians Association

Disclosure: Nothing to disclose.

Chief Editor

Vecihi Batuman, MD, FACP, FASN Huberwald Professor of Medicine, Section of Nephrology-Hypertension, Tulane University School of Medicine; Chief, Renal Section, Southeast Louisiana Veterans Health Care System

Vecihi Batuman, MD, FACP, FASN is a member of the following medical societies: American College of Physicians, American Society of Hypertension, American Society of Nephrology, International Society of Nephrology

Disclosure: Nothing to disclose.


Eleanor Lederer, MD Professor of Medicine, Chief, Nephrology Division, Director, Nephrology Training Program, Director, Metabolic Stone Clinic, Kidney Disease Program, University of Louisville School of Medicine; Consulting Staff, Louisville Veterans Affairs Hospital

Eleanor Lederer, MD is a member of the following medical societies: American Association for the Advancement of Science, American Federation for Medical Research, American Society for Biochemistry and Molecular Biology, American Society for Bone and Mineral Research, American Society of Nephrology, American Society of Transplantation, International Society of Nephrology, Kentucky Medical Association, National Kidney Foundation, and Phi Beta Kappa

Disclosure: Dept of Veterans Affairs Grant/research funds Research

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

  1. Piorry PA, l'Heritier D. Traite des Alterations du Sang. Paris, France: Bury & JB Bailliere; 1840.

  2. Yavuz A, Tetta C, Ersoy FF, D'intini V, Ratanarat R, De Cal M, et al. Uremic toxins: a new focus on an old subject. Semin Dial. 2005 May-Jun. 18(3):203-11. [Medline].

  3. Meyer TW, Hostetter TH. The Pathophysiology of Uremia. Brenner BM, ed. Brenner & Rector's The Kidney. 10th ed. Philadelphia, PA: Elsevier; 2016. Vol 2: 1807-21.

  4. Carrero JJ, Witasp A, Stenvinkel P, et al. Visfatin is increased in chronic kidney disease patients with poor appetite and correlates negatively with fasting serum amino acids and triglyceride levels. Nephrol Dial Transplant. 2010 Mar. 25(3):901-6. [Medline].

  5. Almoznino-Sarafian D, Shteinshnaider M, Tzur I, et al. Anemia in diabetic patients at an internal medicine ward: Clinical correlates and prognostic significance. Eur J Intern Med. 2010 Apr. 21(2):91-96. [Medline].

  6. Camaschella C. Iron and hepcidin: a story of recycling and balance. Hematology Am Soc Hematol Educ Program. 2013. 2013:1-8. [Medline]. [Full Text].

  7. Ganz T. Hepcidin and iron regulation, 10 years later. Blood. 2011 Apr 28. 117(17):4425-33. [Medline]. [Full Text].

  8. Schlieper G, Aretz A, Verberckmoes SC, et al. Ultrastructural Analysis of Vascular Calcifications in Uremia. J Am Soc Nephrol. 2010 Mar 4. [Medline]. [Full Text].

  9. Teng M, Wolf M, Lowrie E, Ofsthun N, Lazarus JM, Thadhani R. Survival of patients undergoing hemodialysis with paricalcitol or calcitriol therapy. N Engl J Med. 2003 Jul 31. 349(5):446-56. [Medline].

  10. Sprague SM, Llach F, Amdahl M, Taccetta C, Batlle D. Paricalcitol versus calcitriol in the treatment of secondary hyperparathyroidism. Kidney Int. 2003 Apr. 63(4):1483-90. [Medline].

  11. Fishbane S, Shapiro WB, Corry DB, Vicks SL, Roppolo M, Rappaport K, et al. Cinacalcet HCl and concurrent low-dose vitamin D improves treatment of secondary hyperparathyroidism in dialysis patients compared with vitamin D alone: the ACHIEVE study results. Clin J Am Soc Nephrol. 2008 Nov. 3(6):1718-25. [Medline]. [Full Text].

  12. Cunningham J, Danese M, Olson K, Klassen P, Chertow GM. Effects of the calcimimetic cinacalcet HCl on cardiovascular disease, fracture, and health-related quality of life in secondary hyperparathyroidism. Kidney Int. 2005 Oct. 68(4):1793-800. [Medline].

  13. El-Agroudy AE, El-Baz A. Soluble Fas: a useful marker of inflammation and cardiovascular diseases in uremic patients. Clin Exp Nephrol. 2010 Jan 26. [Medline].

  14. Fort J. Chronic renal failure: a cardiovascular risk factor. Kidney Int Suppl. 2005 Dec. 99:S25-9. [Medline].

  15. Muscaritoli M, Molfino A, Bollea MR, et al. Malnutrition and wasting in renal disease. Curr Opin Clin Nutr Metab Care. 2009 Jul. 12(4):378-83. [Medline].

  16. Scherer A, Günther OP, Balshaw RF, Hollander Z, Wilson-McManus J, Ng R, et al. Alteration of human blood cell transcriptome in uremia. BMC Med Genomics. 2013 Jun 28. 6:23. [Medline]. [Full Text].

  17. Santos AH Jr, Casey MJ, Wen X, Zendejas I, Faldu C, Rehman S, et al. Outcome of kidney transplants for adults with hemolytic uremic syndrome in the U.S.: a ten-year database analysis. Ann Transplant. 2014 Jul 21. 19:353-61. [Medline].

  18. Tonelli M, Karumanchi SA, Thadhani R. Epidemiology and Mechanisms of Uremia-Related Cardiovascular Disease. Circulation. 2016 Feb 2. 133 (5):518-36. [Medline].

  19. Dioguardi M, Caloro GA, Troiano G, Giannatempo G, Laino L, Petruzzi M, et al. Oral manifestations in chronic uremia patients. Ren Fail. 2016 Feb. 38 (1):1-6. [Medline].

  20. Chuang YW, Shu KH, Yu TM, et al. Hypokalaemia: an independent risk factor of Enterobacteriaceae peritonitis in CAPD patients. Nephrol Dial Transplant. 2009 May. 24(5):1603-8. [Medline].

  21. Seyffart G, Schulz T, Stiller S. Use of two calcium concentrations in hemodialysis--report of a 20-year clinical experience. Clin Nephrol. 2009 Mar. 71(3):296-305. [Medline].

  22. FDA Drug Safety Communication: Modified dosing recommendations to improve the safe use of Erythropoiesis-Stimulating Agents (ESAs) in chronic kidney disease. Available at Accessed: February 3, 2016.

  23. [Guideline] K/DOQI clinical practice guidelines for bone metabolism and disease in chronic kidney disease. Am J Kidney Dis. 2003 Oct. 42(4 Suppl 3):S1-201. [Medline]. [Full Text].

  24. KDIGO clinical practice guideline for the diagnosis, evaluation, prevention, and treatment of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD). Kidney Int Suppl. 2009 Aug. S1-130. [Medline].

  25. Peterson JC, Adler S, Burkart JM, Greene T, Hebert LA, Hunsicker LG, et al. Blood pressure control, proteinuria, and the progression of renal disease. The Modification of Diet in Renal Disease Study. Ann Intern Med. 1995 Nov 15. 123 (10):754-62. [Medline].

  26. Fouque D, Laville M. Low protein diets for chronic kidney disease in non diabetic adults. Cochrane Database Syst Rev. 2009 Jul 8. CD001892. [Medline].

  27. Fakhouri F, Roumenina L, Provot F, et al. Pregnancy-Associated Hemolytic Uremic Syndrome Revisited in the Era of Complement Gene Mutations. J Am Soc Nephrol. 2010 Mar 4. [Medline].

  28. Drüeke TB, Locatelli F, Clyne N, Eckardt KU, Macdougall IC, Tsakiris D, et al. Normalization of hemoglobin level in patients with chronic kidney disease and anemia. N Engl J Med. 2006 Nov 16. 355(20):2071-84. [Medline].

  29. Singh AK, Szczech L, Tang KL, Barnhart H, Sapp S, Wolfson M, et al. Correction of anemia with epoetin alfa in chronic kidney disease. N Engl J Med. 2006 Nov 16. 355(20):2085-98. [Medline].

All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.