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Kidney Diseases

Elevated BUN & elevated potassium

11/01/2007

Question:

Glucose is 90 (scale 65-99, Urea Nitrogen 22(scale 7-25)Creatinine 0.8(scale 0.5-1.2)GRF estimated >60(scale > or = 60. BUN/Creatinine Ratio is 28High(scale 6-22 & potassium 5.7High(scale 3.5-5.3) MyCholesterol total + 284(scale 125-200) HDL 77(scale > OR = 40 LDL 179High (scale < 130. Not feeling well -nausea, indigestion -pain in area-Hiatial Hernia(between rib joining are?? Crappy Dr -Not worrying -what is you educated guess? Tests that I should have?

Answer:

It is difficult to advise you what to do based only on your lab tests, but here are some observations:

BUN (blood urea nitrogen) and creatinine are waste products that are produced by normal metabolic processes in the body and by the breakdown of foods, especially protein. The normal value for BUN is approximately 10-20, and for creatinine, 0.7-1.2. BUN and creatinine are normally excreted by the kidneys, so they accumulate in the blood when a person has kidney failure. Therefore, with renal disease, the BUN and creatinine usually both rise together. However, there are some conditions in which one rises more than the other, and some (as in yours) where the BUN is at the high end of normal while the creatinine is on the low side, causing the ratio to be a little high. A high BUN/creatinine ratio can occur, for instance, in the following conditions: small body size, pregnancy, mild dehydration (for instance, not having had anything to eat or drink for 10-12 hours before the blood test is drawn), heart failure, liver cirrhosis, very high protein diet, GI bleeding (such as an ulcer), and use of steroids such as prednisone.

Your potassium level is on the high side, and again there are several possible explanations. The most common one is that the blood cells have been injured by being pulled through the needle as your blood was drawn, causing them to break and spill potassium into the blood sample (in the tube, but not in your body). This is called a "hemolyzed" sample; labs usually report that the blood is hemolyzed, in which case the sample must be redrawn in order to obtain a true potassium level. If the potassium really is high, this could be due to medications (for instance blood pressure meds called ACE inhibitors, such as lisinopril), or to problems with the adrenal glands, or with the kidneys. Diabetics are especially prone to developing a high potassium level (although I see that your blood sugar, at least on this single sample, is normal). The best thing to do would be to have the test repeated before doing anything more about it.

The most concerning results in your lab tests are your high cholesterol and LDL levels. These should be investigated further and probably will require treatment (diet and/or meds). Your doctor should be able to advise you on this matter. If you are not happy with your doctor, you should find a different one, because high cholesterol levels can increase your risk of heart disease and stroke, particularly if you are a diabetic, a smoker, and/or if you have a family history of heart disease or stroke; so these results should not be taken lightly.

Your doctor should also be able to address the symptoms that you have, and after asking you more questions and examining you, can decide what further tests need to be done.

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Response by:

Mildred   Lam, MD Mildred Lam, MD
Associate Professor of Medicine
School of Medicine
Case Western Reserve University