Good morning,

I have a patron who wonders why first-void urine is recommended in some review articles on diagnosing uncomplicated UTI. In the articles we've looked at (reviews in journal literature as well as UpToDate) the authors always seem to mention that "first void urine" or "collection on arising" is preferred, but these statements are never referenced. I've tried searching PubMed to find research comparing first void samples to those collected at other times, but have come up empty. Practice guidelines always mention the "clean catch, midstream" specimen, but no specific mention of first morning specimen. I first tried a clinical query on the diagnosis of UTI, then went more general with the following strategy: 

("Urinalysis"[MeSH] OR "Urine/microbiology"[MeSH]) AND "Specimen Handling"[MeSH] AND "Time Factors"[MeSH].

This turned up nothing. The ACP Best Practice 167 (laboratory diagnosis of UTI) makes the following statement "early morning samples may harbour greater bacterial counts" but again, this isn't a referenced statement.

Help! How do we find the original evidence that has become so much a part of clinical practice? How do we *know* that bacterial counts are higher or more accurate in the morning?!?


Marcy L. Brown, MLS, AHIP
Medical Librarian
West Penn Hospital - Forbes Campus
2570 Haymaker Road
Monroeville PA  15146
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