Urine colony counts or quantification of urine cultures determines the number of bacterial colonies per mL of urine. This is helpful in assessing whether the bacteria isolated and identified on culture are possible contaminants, normal flora, or significant pathogens. This test is performed by taking a precisely measured amount of urine from a sterile container and streaking it on isolation media. After routine incubation, the number of colonies of bacteria for one or more isolates is counted and calculated per mL of urine.

In order to correctly interpret the results of the test, certain collection procedures must be followed.

1. Best results are obtained by sterile urine collection, preferably by cystocentesis. The site should be cleaned with alcohol or disinfectant to minimize the risk of contamination by cutaneous flora.
   
2. After cystocentesis, the urine should be placed in a sterile container. A plain red top (not serum separator) tube is sterile inside and would be adequate. Be sure to label the tube as "Urine for culture". Only a small amount of urine (even 0.5 mL) is sufficient.
   
3. Special gray top tubes for urine culture transport are acceptable for urine colony count testing. However, broth media (thioglycollate, BHI, etc.) or swabs are NOT accept- able for colony count testing. These are acceptable only for urine culture testing that does not involve quantitation.
   
4. The animal should be off antibiotic therapy for at least 48-72 hours prior to cystocentesis to prevent suppression of bacterial growth.

Results are reported as the number of colonies (or the range) per mL of urine along with the identification of the organism and antimicrobial sensitivity. Less than 1,000 bacterial per mL of urine is considered insignificant, if the preceding guidelines are followed. For urines collected by mid-stream catch or catheterization, less than 10,000 per mL is insignificant. Also, mixed bacterial isolations (2 or more different bacteria) are indicative of contamination and do not accurately reflect the urinary tract infection. This is true for urine colony count as well as for direct plating techniques. The highest reported value for bacterial counts is greater than 100,000/mL.

Urine colony count may be ordered by requesting URINE COLONY COUNT—Test Code 0 3796.

This includes colony count, identification and sensitivity. Turnaround time is 48 hrs.