This culture is designed to quantitate the growth of significant bacteria when collected by the clean catch guidelines or from indwelling catheters. Quantitative culturing of urine is an established tool to differentiate significant bacteruria from contamination introduced during voiding. This test has a reference range of less than 1,000 bacteria per mL. More than 95% of urinary tract infections (UTI) are attributed to a single organism.Infecting organisms are usually present at greater that 100,000 per mL, but a lower density may be clinically important. In cases of UTI where more than one organism is present, the predominant organism is usually significant and others are probably urethral or collection contaminants. When multiple organisms are isolated from patients with indwelling catheters, UTI is doubtful and colonization likely.