I'm sorry to hear about your siblings. I'm guessing this made you have the usual kidney function testing such as urea, BUN, creatinine, measure of glomerular filtration rate, etc. There is actually some new testing that is genetic testing to see if someone has a genetic link to kidney disease. Pretty elaborate but available. You should ask your doctor about this. University hospitals may be able to provide this. What disease did your siblings have or what was the reason they had kidney failure?
You should get genetic testing, and you should check your serum creatinine, and urine routine.