BUN/Crt Ratio??

  1. What does the BUN/Crt Ratio indicate? What does a increase indicate?

    I can not find this information in my Lab Book and I need to know it for my paperwork due Monday for clinicals. I thought some of you all might be able to help me.

    THANKS!!!
    Tricia
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  2. 12 Comments

  3. by   CEN35
    is for the most part meaningless.

    You look at the BUN..... high
    creatinine low......

    dehydrated....

    both normal

    normal

    BUN low creatinine high -probably a recently dialysized patient.

    BUN High, creatinine high newly diagnosed, or known dialysis patient needing diaylsis.

    etc etc

    the ratio? Usually expected to be 10:1 to 20:1, does anybody use it? Not to my knowledge


    me
  4. by   trishfish
    Thanks for the quick response but it does not works with the lab values I have.


    This is how it looks from the lab reports.

    BUN-19-Range(10-20)-----Normal

    Crt--0.5-Range(0.5-15)----Normal

    BUN/Crt Ratio--38-Range(6-25)----Increased

    This pt. has a Hx. of Urinary Retention. Could that be why her ratio is increased. It makes no sense!!!

    Tricia
  5. by   CEN35
    you have me thoroughly confused now? Lets try again?


    me
  6. by   CEN35
    Increase in the BUN/creat ratio:

    Volume defecite r/t an actual decreased intake and/or cardiac output.

    Catabolic states (stress, infection or starvation.

    Ratio decreased:

    Renal dysfunction
    Increased body lean mass
    Increased exercise.

    thats it?


    me
  7. by   wsiab
    Try looking at the patient's diet (specifically protien intake), BUN can be increased by a high protien (meats) diet.
  8. by   trishfish
    I searched on the internet and found that the BUN/Crt ratio will be increased with Renal Insuffiency. She has a BIG history(56yo, L&R CVA's, S/P MI, Amputation of leg due to peripherial vascular disease) of cardiac problems which can decrease renal function.

    Thanks for everyone's help!!!!!!!!
    Tricia
  9. by   msmcvaugh
    I didn't get much from that. How do you determine whether it is dehydration or a kidney problem. mmcv
  10. by   Lisa CCU RN
    Dehydration= increased BUN, normal creatinine.
    Kidney problems=increased BUN and increased creatinine.
    In general....
  11. by   msmcvaugh
    Thanks for that but still wondering, ie 23:24 = kidney related. How is that 10:1? mmcv
  12. by   msmcvaugh
    Opps I meant 2.4, sorry, mmcv
  13. by   Lisa CCU RN
    Here is the explanation from icufaqs.com.

    “Blood Urea Nitrogen” represents the amount of nitrogenous waste in the blood, which is supposed to be cleared by the kidneys. The BUN number always travels accompanied by its partner 1-1-7: creatinine (0.6 – 1.3 mg/dl), but it’s the creatinine number that is actually telling you directly how well the kidneys are working, since a rising BUN by itself can just indicate dehydration, just like a high sodium can. (A high admission hematocrit can be a clue too. Also the prunelike appearance. Then, again, some of us just look that way at baseline. Sigh.)

    The thing to remember is that it's the creatinine that indicates if the kidneys are in trouble or not. High is bad. Someone told me once that if the creatinine increases by one whole number, it represents the loss of a third of the patient's kidney function, which means you can't do that very often!

    So look at the BUN and creatinine as a ratio: normal would look like 12/ 1.0, right? A high BUN with a normal creatinine means a dry patient whose kidneys are still okay – if she gets hypotensively dry, her kidneys may become unhappy as a result of being under-perfused. Something like BUN of 70 with a creatinine of 1. High ratio. If the creatinine starts to rise, then real trouble is coming, because the kidneys are getting into trouble at the tissue level, maybe in the form of acute tubular necrosis, never a picnic. Might look like 70 / 3.0 – higher numbers, lower ratio. Comparison is everything, so take a look at a couple days' worth of chems and see if the creatinine has been going up, down or sideways.
  14. by   RISN
    an increased BUN and creatinine means renal failure

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