Anonymous asked in Science & MathematicsMedicine · 1 month ago

I kept my urine sample unrefrigerated for 5 hours, the lab found an infection, is this the reason?

So I did a urine test and I left it in room temperature (under 30C) for 5 hours before taking it to the lab. I had no idea it has to be very fresh or put in the refrigerator. I got my results and it says I have an infection, could it be due to the bad storing? I’m just wondering if I have to repeat it.



Nothing “fishy” is here, Sherlock. 

I just feel embarrassed to inform my doctor that I didn’t store it well. When I googled, I found “the bacteria could multiply” and thought maybe this is the reason.

7 Answers

  • 1 month ago

    You should have tasted it first before submitting.

  • 1 month ago

    The College of American Pathologists (CAP) inspectors who go into labs to make sure things are done appropriately and can ding a lab for violations and the checklist states that urine must be tested within one or two hours or it must be refrigerated. 

    The reason for that is obvious and that is E coli replicates every 20 minutes in rich culture media but urine is not rich and so it takes 1 hour to double up the number. 

    Assume one collects a urine that isn't a clean catch and ends up with 5,000 CFU's of E coli if immediately cultured. One waits one hour and that number changes to 10,000 CFU's, 2 hours 20,000, 3 hours 40,000, 4 hours 80,000 and finally five hours one ends up with 160,000 CFU's per ml. Anything over 20,000 can be clinically significant. 

    What determines if a person has an infection or not is determined clinically by symptoms as Diane said. Sometimes a urinalysis and culture are not even needed. In questionable cases where it is performed then yes the test is invalid and you should retake the test. Inform the doctor what happened. 

  • Mike
    Lv 7
    1 month ago

    An infection would not give the same results as poor storage would.  You likely have an infection, you might need a blood test to determine what and for the doctor to determine the best medication.

  • 1 month ago

    yes, it is a possibility, room temp allows anything in there to grow, we refrig right away or put it in the culture collection tube that inhibits over growth. This is one reason we never culture a urine from home too, we collect a fresh sample. you should have spoken up as the test costs hundreds and you may be given a wrong diagnosis. Unless you have symptoms, i would repeat it.

    Source(s): ER PA
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  • Sandy
    Lv 7
    1 month ago

    urine should be refrigerated if not tested in a timely manner. 5 hours is within that time frame though, so the test results are valid.

  • Rick
    Lv 6
    1 month ago

    nope, urine is very acidic, and the infection has to be pretty tough to grown there ................ 

  • 1 month ago

    I`m no urine expert but something smells "fishy" here.

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