How does cellulitis relate to out-of-whack serum creatinine and creatinine clearance?

AgentBeast, MSN, RN · Nov 12, 2012

Nothing is wrong with this patient's kidneys at all based on what you've presented. High serum creatinine levels and a low creatinine clearance would be indicative of some sort of renal issue. Low serum creatinine levels and high creatinine clearance indicate the kidney's are working as they should. The low creatinine level and high creatinine clearance might be indicative of a problem somewhere else and it might not. There isn't enough information here to say without making wild assumptions.

PalmHarborMom · Nov 12, 2012

The patient's serum creatinine levels are OK. The Creatinine clearance is elevated but that can be due to eating lots of meat, pregnancy or vigorous exercise. Normally it is when the creatinine clearance is low that there is a problem.

Double-Helix, BSN, RN · Nov 12, 2012

Think about what these values mean:

Creatinine is a product of breakdown of muscle. It's a waste product. The kidneys are responsible for removing waste products from the blood.

If the kidneys are performing poorly, they will not filter waste effectively. That will lead to waste products building up in the blood. If the patient has poor kidney function, would you expect creatinine to be high or low?

Creatinine clearance is a comparison for the creatinine in the urine and creatinine in the blood. It measures how effectively the kidneys are breaking down waste products. Clearance is measured in mL/minute. Now think... If the normal clearance is about 100mL/min, is a clearance of 300 mL/min better or worse?

Your patient appears to have excellent kidney function.

You also need to consider how these tests are performed. Many times, lab results are pre-programmed to calculated based on available data. In order to perform an accurate creatinine clearance, you need a 24 hour urine collection, and a blood test. Did the patient have a 24 hour urine collection, or a simple urinalysis upon admission? It's possible that the computer automatically calculated creatinine clearance based on the urinalysis data, when it was not accurate to do so.

Samian Q · Nov 12, 2012

But this site says normal CrCl is 88 to 128 for females:

Creatinine clearance: MedlinePlus Medical Encyclopedia

This woman's CrCl is way above 128

psu_213, BSN, RN · Nov 12, 2012

But this site says normal CrCl is 88 to 128 for females:
Creatinine clearance: MedlinePlus Medical Encyclopedia
This woman's CrCl is way above 128

What does creatinine clearance mean? What does a low Cr Cl tell you about the kidneys? Then, what would a high level tell you? What do you think it means in the creatinine clearance is high yet the pt's serum creatinine is normal? Don't just go based on what a website or book tells you what the normal values are. Try to understand this in terms of the processes of the body.

Double-Helix, BSN, RN · Nov 12, 2012

But this site says normal CrCl is 88 to 128 for females:
Creatinine clearance: MedlinePlus Medical Encyclopedia
This woman's CrCl is way above 128

Would that mean her kidneys are working worse than expected or better than expected?

nurseprnRN, BSN, RN · Nov 12, 2012

Suggestion: The excellent "Laboratory and Diagnostic Tests with Nursing Implications," by Joyce Lefever Kee. I believe the 8th edition is the most current. Free 2-day shipping for students from Amazon, and you'll be using that book for many years. I still use mine.

If you didn't know yet, you'll find out that NCLEX (and your faculty) want you to know those nursing implications, and Kee is excellent at explaining the whys that the above posters are prompting you about.

hodgieRN · Nov 12, 2012

You also have to remember that an abnormal lab value doesn't necessarily equal bad. If someone has a creatinine level of 0.5, it is abnormal, but the kidneys are working so well that the level is low (which is actually good). So, if the clearance is high, would that mean the level is bad?

(FYI) If the labs were reversed meaning that the creatinine level was high and the clearance value was low, you can have kidney issues from cellulitis if the pt is septic from the infection The reason is when you have an infection, a septic reaction can lead to renal failure. Sepsis is an inflammatory reaction from the infection's endotoxins. Renal failure is a major complication of sepsis. Again, this would be found in lab values opposite of your pt.

But what from what we are reading, it doesn't appear there is anything wrong with the kidneys. The creatinine level is normal and she has great clearance.

lalopop86 · Nov 12, 2012

Suggestion: The excellent "Laboratory and Diagnostic Tests with Nursing Implications," by Joyce Lefever Kee. I believe the 8th edition is the most current. Free 2-day shipping for students from Amazon, and you'll be using that book for many years. I still use mine.

If you didn't know yet, you'll find out that NCLEX (and your faculty) want you to know those nursing implications, and Kee is excellent at explaining the whys that the above posters are prompting you about.

THANK YOU GRNTEA!

Esme12, ASN, BSN, RN · Nov 12, 2012

Any disease or condition that affects the glomeruli can decrease the kidneys' ability to clear creatinine and other wastes out of the blood. When this occurs, the blood creatinine level will be increased and the creatinine clearance will be decreased because not as much creatinine is able to be excreted in the urine.

http://labtestsonline.org/

A number of diseases and conditions can affect kidney function.

A decreased creatinine clearance rate may also occur when there is decreased blood flow to the kidneys as may occur with congestive heart failure, obstruction within the kidney, or acute or chronic kidney failure. The less effective the kidney filtration, the greater the decrease in clearance.
Increased creatinine clearance rates may occasionally be seen during pregnancy, exercise, and with diets high in meat, although this test is not typically used to monitor these conditions

Creatinine Clearance: Test Sample