BUN/ Creatinine and the Evaluation of Renal Functioning
Creatinine .7 – 1.4 – BUN 7-24 – GFR- Glomerular Filtration Rate
Here is My Renal BUN/Creatinine Evaluation of Renal Conditions
BUN stands for blood urea nitrogen. Urea nitrogen is what forms when protein breaks down. The interesting thing about BUN is that protein is initial broken down into the byproduct of Ammonia which is toxic to the body. It is then sent to the liver to be further broken into blood urea nitrogen which is able to be filtrated out of the body- That is why patients with liver disease have increased level of ammonia and need lactulose and also why low BUN is liver disease.
Also, since BUN is the byproduct of Protein breakdown renal patients are also on a low protein diet to decrease the amount of waste BUN.
BUN low and Creatinine low are generally not indicators of anything Acute
Creatinine is the byproduct of muscle breakdown and is only filtered through the kidneys that is why it is indicative it increases there is a problem inside the kidneys.
Both Blood Urea Nitrogen (BUN) and the Creatinine are important when they are high. They are specific to the kidney and there functioning. These are Kidney Labs to be taken together in the evaluation of kidney functioning.
The Glomerular Filtration Rate-(GFR) the GFR is the actual evaluation of how the kidney is working. It is only used if both the BUN and creatinine is elevated. It is used in chronic to stage the level of CKD and acute to evaluate what phase of Acute Kidney Injury AKI or Acute Kidney Failure a Person is in and how well their kidney is functioning.
STEPS to Evaluating Kidney Labs
First step is always looking at the BUN if it is high you then look at the Creatinine next if it is normal it is most likely dehydration caused by outside the kidney.
Second if you see that the BUN is high and you look at the creatinine and it is also high. Think is this an ACUTE process going or CHRONIC condition Chronic Kidney Disease (CKD).
Chronic= High BUN and High Creatinine
If both are high you then look at the Glomerular Filtration Rate-(GFR) the GFR is the actual evaluation of how the kidney is working. Once a person is identified as a CKD they begin to be staged by their GFR- Less than 15! A decision is made whether they will be on dialysis or not. The GFR in CKD never gets better and can only slow the progression through medication sugar control.
Stage Description (GFR)
1 Kidney damage with normal kidney function 90 or above
2 Kidney damage with mild loss of kidney function 89 to 60
3a Mild to moderate loss of kidney function 59 to 44
3b Moderate to severe loss of kidney function 44 to 30
4 Severe loss of kidney function 29 to 15
5 Kidney failure Less than 15