Quantitative unspun-urine microscopy as a quick, reliable examination for bacteriuria

Masahiro Hiraoka, Y. Hida, Y. Mori, H. Tsukahara, Y. Ohshima, H. Yoshida, M. Mayumi

Research output: Contribution to journalArticlepeer-review


The diagnosis and treatment of urinary infection are often delayed, causing renal damage, largely because of the unavailability of quick, accurate, diagnostic examinations. Three hundred and twenty-five urine samples from 130 patients were examined for significant bacteriuria using the standard culture method. The urine samples were also examined using the Gram-stain method and quantitative unspun-urine microscopy. When particles could not be distinguished definitely as bacilli by quantitative microscopy, the unspun urine was examined on a slide glass using oil-immersion microscopy at × 1000 magnification. Significant bacteriuria in 37 urine samples was detected by bacterial culture. Using quantitative microscopy, rods were found in 30, cocci in a chain in 3, and indefinite particles in 44 samples. In the 44 indefinite samples, oil-immersion microscopy was able to distinguish rods in one, cocci in a chain in one, cocci in a cluster in two, and negative in 40, which were confirmed by culture as rods, streptococci, staphylococci, and negative, respectively. The quantitative microscopy method was similarly reliable (94.6% sensitivity, 99.3% specificity) for diagnosis of significant bacteriuria when compared with the Gram-stain method (89.2% sensitivity, 98.6% specificity). Quantitative unspun-urine microscopy, confirmed by oil-immersion, is a quick, reliable method for diagnosis of significant bacteriuria, and is considered to be useful for early diagnosis of urinary infection.

Original languageEnglish
Pages (from-to)125-132
Number of pages8
JournalScandinavian Journal of Clinical and Laboratory Investigation
Issue number2
Publication statusPublished - 2005
Externally publishedYes


  • Diagnosis
  • Renal damage
  • Staphylococcus
  • Streptococcus
  • Urinary infection
  • Urinary microscopy

ASJC Scopus subject areas

  • Clinical Biochemistry


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