Urinecontaminated

Urinecontaminated is a term used to describe urine samples whose test results may be compromised by extraneous material or organisms not originating from the urinary tract. Contamination can affect urinalysis and culture results, potentially leading to misdiagnosis or inappropriate treatment.

Causes of urine contamination include improper collection techniques, such as not cleaning the genital area, using non-sterile containers, collecting a sample too soon, or delaying processing after collection. Different methods carry varying risks: clean-catch midstream samples are especially prone to vaginal or skin flora contamination, while catheterized samples have lower contamination rates but carry procedural risks.

Implications of contamination include false positives for infection, mixed flora on culture that reflect skin or vaginal contaminants rather than true urinary pathogens, and skewed chemical measurements on dipstick testing. Contamination can obscure true results and complicate clinical decisions, sometimes necessitating repeat sampling.

Detection of a contaminated specimen often relies on laboratory indicators such as the presence of numerous squamous epithelial cells, mucus, or debris on microscopic examination, mixed flora on culture, or results that do not correlate with the patient’s symptoms. When contamination is suspected, a repeat sample is typically recommended.

Prevention focuses on proper collection and handling. Key steps include providing clear collection instructions, using sterile containers, ensuring proper perineal cleaning, collecting a clean-catch sample when appropriate, and prompt transport and processing. In some cases, a catheterized specimen or alternative sampling method may be indicated if infection is suspected but contamination cannot be avoided.

See also: urinalysis, urine culture, specimen contamination, laboratory quality control.