I am an adult nephrologist and do not see infants or children. I am unaware of any blood or urine tests that can diagnose Nephrocalcinosis in an infant or fetus. I would suggest that you consult with a geneticist or a pediatric nephrologist about such testing. An ultrasound examination can sometimes diagnose Nephrocalcinosis in an adult but I do not know if it can do so in an infant. The ultrasound test is not the definitive test for this disease. I suggest further consultation with a pediatric specialist in your country.