My pharmacy doesn't have a strainer for kidney stones. What should I use?

I went to the hospital and the doctor but they never gave me a strainer. My doctor said I needed one though but my local pharmacists said they dont have any. Anything else I can use to catch the stone?My pharmacy doesn't have a strainer for kidney stones. What should I use?
If you have a fine mesh strainer, you could use that. To be sure that you catch any stone that may be expelled (some stones can be as small as a grain of sand), you may try lining the strainer with a coffee filter.
Go back to the hospital and ask them for a strainer. They will give you one. If all else fails you can use a fine mesh sieve but the hospital will give you a strainer if you go back and tell them they forgot to give you one.
why would a pharmacy carry such an item? They aren't medical supply houses...they just sell drugs.
coffee filter thats what I used