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Test Code C Urine Urine Culture

Important Note

The specimen source is required on all orders and specimens.

  • Cath Urine
  • Clean Catch
  • Suprapubic Asp

Additional Codes

Cerner

NextGen

C Urine

Culture Urine

Useful For

The Urine Culture is used to assist in the diagnosis of kidney function and evaluating the presence of urinary tract infections.

Several methods are involved in the analysis of urine cultures:

  • The macroscopic examination of urine cultures
    •  The physical examination of flora present
    • A qualitative evaluation of organisms present on plate is conducted. Biochemicals and molecular methods are used in the identification and sensitivity of organisms present.

Methodology

Depending on the growth and quantity present in culture will determine what methods will be employed.

  • The Vitek 2
    • The Vitek 2 is automated machine capable of identifying and determining sensitivity of microbial isolates.
  • Maldi
    • An automated machine that utilizes mass spectrometry in the identification of microbial isolates.

Patient Preparation

First morning midstream clean-catch is the preferred specimen for culture.

Collection Instructions

Specimen Requirements

Preferred Volume

10 mL uncentrifuged and unpreserved, random clean catch or catheterized urine.

Minimum Volume

0.1mL uncentrifuged and unpreserved, random clean catch or catheterized urine.

Container
  • Preferred: BD Vacutainer Urine C&S tube (grey tube)filled to the minimum fill line

  • Sterile container without preservative

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Stability
  • ≤ 2 hours at room temperature
  • ≤ 24 hours refrigerated at 2-8° C if refrigerated within 2 hours of collection
  • BD Vacutainer Urine C&S tube (grey tube) (Preserved) may be cultured up to 48 hours after collection without refrigeration.

Rejection Criteria
  • Improperly/mislabeled specimens
  • Improperly stored specimens
  • Insufficient specimen volume
  • Specimens received in collection containers potentially contaminated (i.e leaky containers).
  • Specimens contaminated with fecal matter.

Result Reporting and Reference Values

  • Negative Cultures
    • No growth after 18-24 hours of incubation in clean catch specimen.
    • No growth after 48 hours of incubation if catheterized and suprapubic aspirate specimens.
  • Positive Cultures
    • Include the quantitation of the organism(s), complete identification and susceptibility testing results along with any mixed flora present.

Reflex Testing

  • Susceptibility testing:
    • For Clean Catch specimens, susceptibility testing is done on pathogens if there is only one or two organisms and the quantitation is >10,000 CFU/ml.
      • Susceptibility testing on lower colony counts performed only by special request of the physician.
    • For catheterized and suprapubic aspirate specimens, susceptibility testing will be conducted on all organisms present.
    • Sensitivity maybe referred to another culture if same patient, same isolate within three days of collection from one another.

Limitations

Because most antibiotics concentrate in urine, negative urine cultures are possible following treatment of a UTI by an antibiotic that is only partially effective. For this reason, urine cultures collected to determine whether a course of therapy was effective should be collected 2-4 days after discontinuance of the antibiotic.

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