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Nephrology/High BUN/Creatinine


Hello.  Beginning around summer of 2011, I had a blood test come back reporting high levels of Urea Nitrogen (BUN) and BUN/Creatinine Ratio. This was the first ever time this occurred.  On follow up blood work later in 2012, and the levels were high again. I woke up dehydrated (more than unusual) but drink several glasses of water before getting blood drawn. The doctor stated again "I was a little dehydrated" with BUN of 29 (should be 7-25) and a BUN/Creatinine Ratio of 29 (should be 6-22). On the last test,they were both lower (24, and 25).

I've read about possible causes.. I'd say my diet is moderate protein intake, though it's not much different than in years past. I do have urinary retention, but this is a side effect of an antidepressant medication I'm on... and I've been this way for many, many years as well. My father has low kidney function, along with many other conditions... So I'm just keeping a close eye on this. My doc doesn't seem concerned, as everything else is normal, and I'm healthy (30 years old), 140lbs or so, etc..

I do drink a lot of soda, and I can't seem to draw any conclusion that diet soda can cause issues with kidneys.  There are days I drink over 100 oz (though this isn't typical) but it's always diet.  I enjoy it and look forward to it and don't want to push it away unless it's truly causing the problem.


Thanks for asking my help on "Allexperts".

I have discussed the causes of high BUN/Creatinine ratio many times on this forum. If you can look up my past responses, you will find a discussion of the causes of elevated BUN and BUN/Creatinine ratio.

There is scientific evidence to suggest that diet soda can cause a faster decline in kidney function.

I'd like to point you to a discussion on this subject here:

All of the participants were women, so Lin can't say for sure that the association holds for men, although she says there is ''no biological reason to think it wouldn't."


Dr. Shah


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Dr. Shamik Shah, MD, DNB (Nephrology), ISN Fellow


I can answer all questions related to kidney diseases, hypertension, plasmapheresis and kidney transplantation. I am an Indian-Board certified Nephrologist. I was a post-Doctoral Scholar at the Division of Nephrology & Hypertension,Department of Medicine, University of California, San Diego. My area of interest is Critical care Nephrology and Acute Kidney Injury.

Please mention the units in which your lab results were reported and the normal reference range for your laboratory.

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Ten years as a Critical Care & Transplant Nephrologist

International Society of Nephrology
Indian Society of Nephrology
Indian Medical Association
European Renal Association

- Shah SH, Cerda J. Acute Tubular Necrosis; Lerma, Edgar V., Rosner, Mitchell eds. Clinical Decisions in Nephrology, Hypertension and Kidney Transplantation. Springer ISBN 978-1-4614-4453-4, pp. 191-198
- Shah SH, Cerda J. Management of Acute Kidney Injury; Lerma, Edgar V., Rosner, Mitchell eds. Clinical Decisions in Nephrology, Hypertension and Kidney Transplantation. Springer ISBN 978-1-4614-4453-4
- Cerda J, Tolwani A, Shah SH, Ronco C. Continuous Renal Replacement Therapies in Modeling and Control of Dialysis Systems edited by Azar AT, Springer-Verlag, Heidelberg, Germany (In Press)
- Shah SH, Cerda J, Kellum JA. Acute Kidney Injury in Special Circumstances. John Kellum, Jorge Cerda, eds. Renal and Metabolic Disorders, Oxford University Press (In press)
- Shah SH, Mehta RL. “Anticoagulation in CRRT: Is Citrate better?”; Vineet Nayyar Ed. Critical Care Update 2009, Jaypee Brothers (In press)
- Shah SH, Mehta RL. “Non-dialytic management of acute kidney disease”; Evidence based Nephrology, BMJ, (In press)
- Shah SH, Mehta RL. “Epidemiology of Community-acquired AKI”; Ronco C, Bellomo R, Kellum J Eds. Critical Care Nephrology, Saunders. ISBN 1-4160-4252-0
- Abdeen O, Shah SH, Mehta RL; “Dialysis therapies in the surgical intensive care unit”; William Wilson, Christopher Grande, David Hoyt Eds. Trauma: Resuscitation, Anesthesia, and Critical Care, Informa Healthcare, NY 2007. ISBN 0-8247-2920-X
- Shah SH, Mehta RL. Acute kidney injury in critical care: time for a paradigm shift? Curr Opin Nephrol Hypertens. 2006 Nov;15(6):561-5.
- Shah, SH, Soroko S, Lischer E, Mehta RL. Delivered vs. Prescribed dose of Dialysis in Hospitalized Patients: Results of an Audit. J Am Soc Nephrol 17(Abstracts Issue): 2006, 107A.
- Shah SH et al “Biochemical Nutritional Parameters in Non-vegetarian and Vegetarian CAPD patients” Perit Dial Int 2001; 21 Suppl 2: S1-182

MBBS, MD (Internal Medicine), Diplomate of National board (Nephrology), ISN Fellow

Awards and Honors
Educational Ambassador of the International Society of Nephrology 2010
Fellowship of the International Society of Nephrology 2005.
Young Investigator Award by the International Society of Peritoneal Dialysis 2001

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