Checking Urine to Diagnose… Pneumonia?

Somewhere, every minute, a patient with a fever is getting a chest X-Ray to look for pneumonia and a urinalysis to look for UTI. New research by UC Davis biochemist Carolyn Slupsky and others may one day prove that there’s enough in urine to diagnose pneumonia, on its own:

Using technology known as nuclear magnetic resonance spectroscopy, the researchers were able to identify a chemical “fingerprint” for the type of pneumonia caused by the bacterium Streptococcus pneumoniae, and compare this to the chemical fingerprints for other types of pneumonia and noninfectious lung diseases.
Findings from the study, conducted by Slupsky and colleagues in Canada and Australia, are discussed in a research profile in the December issue of the Journal of Proteome Research. A patent is pending on the diagnostic procedure.
“This is the first study to demonstrate that NMR-based analysis of metabolites in urine has the potential to provide rapid diagnosis of the cause of pneumonia,” said Slupsky, an assistant professor in UC Davis’ departments of Nutrition, and Food Science and Technology. She is also a faculty member in UC Davis’ Foods for Health Institute.
…Currently, pneumonia is diagnosed by a combination of clinical symptoms, X-rays and analysis of a patient’s blood or sputum by bacterial culture. Such tests usually take more than 36 hours to complete and tend to yield a high rate of false-positive results. Previous studies have shown that more than 80 percent of patients admitted to the hospital with pneumonia are misdiagnosed, leading to delays in treatment with the appropriate antibiotic.

OK, let’s not overstate the case, here. The only way they’re arriving at a figure of 80% misdiagnoses (which isn’t discussed in the paper) is if they’re looking at a chest x-ray and history and trying to guess the causative organism, which is notoriously difficult and never used as a basis for treatment. Instead, broad-spectrum antibiotics are started while maybe blood and/or sputum cultures are cooking. In many, many cases, the patient improves and cultures don’t compel a change in antibiotic regimen.
Where Slupsky’s urine-checker might one day fit in is if a patient has a story and X-ray consistent with Strep pneumo and a urine test shows Strep pneumo metabolites, a clinician may consider a more narrow-spectrum regimen (which might be better for society as it would discourage antibiotic resistance). But we’d have to see a lot of impressive data on the safety and efficacy of this urine-based approach before we considered changing the current standard of care.

More from Dr. Slupsky’s paper…
Press release: Fast, Accurate Urine Test for Pneumonia Possible, Study Finds
Image credit: Flickr user Ritalin