Is it possible to have kidney stones, but not have any evidence of them in urine samples or ultrasounds?

Yes. These stones may be too small see on ultrasound and a routine urinalysis may easily miss stones as well. The best test for diagnosing the majority of stones in the urinary tract is a ct scan without contrast. This will detect the majority of kidney stones but a few may be missed occasionally.
Kidney stones. Kidney stones may present as sand in the sediment of urine can only be detected when the urine is strained.

Related Questions

Might someone have kidney stones, but not have any evidence of them in a urine sample or an ultrasound?

Yes. Having kidney stones is detected by radiological means. Tis includes plain films, ultrasound, and ct scans. The gold standard test is the ct scan but it emits a lot of radiation. Ultrasound is also a good study but much more limited. It can certainly miss small stones in the kidney and will miss all stones in the ureter (kidney tube) because ultrasound cannot adequately visualize the ureter. Read more...
Finding kidney stone. Yes. The best way to find small stones is with a high resolution cat scan. They can be easily missed with ultrasound, and often do not cause blood in the urine on a consistent basis. Read more...
Yes. There is not always blood in the urine with a stone and ultrasound is really not the best imaging study for kidney stones. Read more...

Ecoli in urine and 8 mm kidney stone?

Urine culture. you should have urine culture and be treated with antibiotic if urine culture is positive and for kidney stone if CT revealed obstruction stone should be remove. Read more...