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

  1. 0
    So one of the patients I care for tomorrow was admitted for facial cellulitis.

    Her serum creatinine is listed at 0.7 and her Creatinine Clearance (CrCl) is at 292.86, according to the labs.

    The serum creatinine's low and the CrCl is astronomical. She doesn't have any other medical history.

    I simply don't get it. How on earth are her kidneys in bad shape? Doesn't creatinine levels tell you how well or how poorly kidneys are functioning?

    Get the hottest topics every week!

    Subscribe to our free Nursing Insights: Student Edition newsletter.

  2. 10 Comments...

  3. 1
    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.
    Esme12 likes this.
  4. 1
    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.
    Esme12 likes this.
  5. 2
    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.
    CarrieGL and gatoraims RN like this.
  6. 0
    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
  7. 1
    Quote from delrepublica1776
    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.
    Esme12 likes this.
  8. 1
    Quote from delrepublica1776
    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?
    Esme12 likes this.
  9. 0
    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.
  10. 0
    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.
  11. 0
    Quote from GrnTea
    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!


Nursing Jobs in every specialty and state. Visit today and Create Job Alerts, Manage Your Resume, and Apply for Jobs.

A Big Thank You To Our Sponsors
Top