How to Strain Urine for Kidney Stones

When passing a kidney stone, straining your urine allows your physician to send the stone for testing. This analysis reveals the composition of the kidney stone and enables your doctor to institute a plan to possibly prevent the formation of future stones 1. While straining the urine can be inconvenient, it is important to complete this task for diagnosis when passing a kidney stone.

Drink plenty of fluids, which can aid in the stone's passage from the kidneys to the urethra. It is important to remain hydrated and continue drinking fluids. The more fluids you ingest, the more likely the stone will pass quickly out of your system.

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Place a urinal in the toilet. This typically fits under the top lid of the toilet. If a urinal is not available, urinate into a clean container that allows the liquid to be easily poured through the strainer. Urinate as needed into the urinal or container in accordance with your doctor's instructions. This is typically from the first onset of kidney stone pain until passage of the stone is complete. Depending on the size and shape of the stone, this may take a few hours or as long as a few days.

Strain the urine. After each visit to the bathroom, pour the urine from the urinal or container through the strainer. The stone should be visible after the urine has been strained. If a medical strainer is not available, a coffee filter also works well. Collect any kidney stones that are left after straining 1. If the stone was crushed prior to passage, there may only be fragments of the stone to collect, but collect all the matter for testing. Your physician or lab should provide a specimen container to place the stone in for delivery to the lab facility.

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Deliver the stone to the lab or doctor’s office for pathological testing. Results from the tests should be available in a few days and will provide the doctor with insight into the causes of the kidney stone. This new information may lead to dietary changes to help combat future stone formation.