Had ua which shows moderate microsccopic blood in urine but when cultured shows no RBC or WBC or protein. How can be moderate blood but no rbc?

Wrong test. A urine culture looks for bacteria growing, it can not detect red blood cells hematuria without visible red blood cells can result from hemolyzed rbcs or rhabdomyolosis. Rbcs are frequently seen without protein in urologic disease.
Hematuria. False positives include contamination with vaginal or menstrual bleeding, betadine® solution, myoglobinuria (breakdown of muscle cells in the urine), dehydration, and bacterial enzymes from vaginal or bladder infections. Vitamin c can produce false negative tests as can a very acid urine (ph 5.0 or less) or test strips that have been overexposed to air or are outdated.