Doing a urine sample wrong can cause false results
Why do lupus patients need to give a urine sample every 3 months?
Around 40% of systemic lupus erythematosus patients develop kidney inflammation (nephritis).
Some groups get it more often, as high as 80% in Afro-Caribbean women and 50-55% in African American women
Finding excess protein in the urine (proteinuria) is how we identify lupus nephritis at its earliest stages.
How can the urine sample be inaccurate?
If there are white blood cells, red blood cells, and other substances contaminating it from the vagina or foreskin, this can cause an artificially high amount of proteinuria
If you collect it after exercising a lot, or in the afternoon it can be artificially high (orthostatic proteinuria)
How to collect a urine sample optimally (PRINT THIS OUT AND KEEP IT HANDY):
Why this is important: If you get into the habit of doing this correctly, you will save yourself from having to repeat it or from having to collect an unnecessary 24 hour urine collection (which is cumbersome to do)
- Always try to collect your sample first thing in the morning (either the 1st or 2nd void)
- Hydrate. Drink at least 8 glasses of water daily for a few days before the collection (unless your doctor has you on a water restriction)
- Collect a "mid-stream, clean-catch" urine sample:
- 1st wash your hands.
- Carefully remove the lid from the urine sample cup (making sure not to touch the inside of the container or cover) and lay the cover with the inside section facing up.
- If you are giving a urine culture as well to make sure you do not have a urinary tract infection, use a sterile cup.
- Place the cup on an easy-to-reach surface.
- Pull apart the labia (if you are female) or retract the foreskin (if you are a male) with one hand.
- Using your other hand, you wipe the urethra three times with three sterile wipes (front to back if you are a female). Continue to keep the labia or foreskin retracted with one hand and grab the cup with the other hand.
- You then urinate the first couple of seconds into the toilet (this gets rid of any bacteria that may have been in the urethra), and then urinate into the cup to the fill line.
- You should empty the last part of your urine into the toilet again (which is why the term “midstream”). You should immediately put the lid securely on the cup, making sure not to touch the inside of the cover or the container.
- Make sure and place the lid securely on the cup prior to flushing the toilet to prevent contamination from aerosolized droplets from the toilet (thanks to ANON for this great recommendation).
PRINT this out and keep it handy
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The Lupus Encyclopedia
Fanouriakis A, Kostopoulou M, Cheema K, et al. 2019 Update of the Joint European League Against Rheumatism and European Renal Association–European Dialysis and Transplant Association (EULAR/ERA–EDTA) recommendations for the management of lupus nephritis. .Annals of the Rheumatic Diseases 2020;79:713-723.
Note that Dr. Thomas' posts are for informational purposes only, and are not meant to be specific medical advice for individuals. Always seek the advice of your healthcare provider with any questions regarding your own medical situation.
DONALD THOMAS, MD