The routine use of molecular urine testing – particularly multiplex PCR assays – for diagnosing UTIs in nursing homes has become increasingly controversial.
A recent McKnight’s article highlights a call on providers to stop using routine PCR urine tests for UTIs, “the most common infection in nursing homes,” citing patient safety concerns, escalating costs, and the lack of proven clinical benefit. The cited statement reiterates that long-term care settings “should continue to use standard-of-care culture techniques when appropriate to diagnose and treat UTI.”
The article details a recent PALTmed panel of post-acute medical care experts, who claim “using PCR, a polymerase chain reaction test that provides fast results, may lead to overdiagnosis of UTIs and the misuse of antibiotics.” The PALTmed team originally reported their findings in the Journal of the American Medical Directors Association.
Background: Molecular urine tests (e.g., multiplex PCR) detect bacterial DNA in urine specimens, offering rapid results compared to traditional culture-based diagnostics. PCR tests are a subject of concern when acknowledging the risk of false positives that lead to over-diagnosis. False positives in urine testing can derive from the detection of nonviable organisms, contaminants, and colonizing flora.
A common issue facing long-term care professionals when performing molecular urine testing is the presence of asymptomatic bacteriuria (ASB). Current industry studies indicate that up to 50% of nursing home residents have ASB, which does not require treatment. Beyond asymptomatic bacteriuria, false positives can also occur due to specimen collection error on the part of medical staff, as improper specimen collection can inflate positive rates.
Why does this matter? The over-diagnosis of urinary tract infections in nursing home residents can lead to excessive and unnecessary prescribing of antibiotics. Antibiotic overuse can then often lead to antimicrobial resistance within the affected patient. The likelihood of adverse events, such as drug toxicity or microbiome disruption, can then disrupt normal gut flora, leading to an increased risk of C. diff overgrowth and infection.
For nursing home administrators and clinical staff, the costs are not just limited to the increasing price to perform PCR testing (per McKnight’s, “UTI multiplex testing costs about 70 times higher than urine cultures; the median cost for a multiplex panel was $585 in 2023, compared with $8 for a urine culture”), but also when such adverse events then result in costly patient hospitalizations.
The evidence of limited benefit in using molecular PCR urine tests compared to these potential costs, along with the additional challenges posed to nursing home stewardship and delivery of proper treatment, is why the panel maintains that culture techniques for urine testing remain the industry standard.