Print  |  Email
Laboratory: Clinical Microbiology
Test Name:
Test Code: TIS
Clinical Information:
Test Indications:
Bacterial culture of renal calculi may be useful in the management of patients with urinary infection in the setting of nephrolithiasis.  Several studies have demonstrated that culture of urine does not always identify the bacterial pathogen in infected renal stones.  Knowledge of the pathogen identity and susceptibility profile may assist the clinician in choosing appropriate antimicrobial therapy for patients with struvite (magnesium ammonium phosphate) stones.  This information can also be helpful in tailoring antimicrobial therapy for patients that develop SIRS (systemic inflammatory response syndrome) following stone removal.  Further, culture of renal calculi may provide supportive evidence that renal stones are serving as a persistent nidus of infection for complicated patients having recurrent urinary tract infections.  This in turn can help inform future management decisions (i.e., how aggressive to be regarding calculi removal).

Renal, prostatic, and bladder calculi for bacterial culture (aerobic) may be submitted to the microbiology laboratory at the discretion of a physician/urologist to assist in the management of patients with complicated urinary tract infections in the setting of nephrolithiasis.
Clearly indicate on the microbiology requisition the specimen site, the specimen type, and the test(s) requested (e.g., bacterial culture - aerobic). 
Indicate the current antimicrobial therapy the patient is receiving on the requisition.
If biochemical analysis of a urinary stone is also required, please submit a separate specimen to Clinical Biochemistry.  Test information and specimen submission requirements are available online at:

Patient Preparation Instructions:
Renal/prostatic/bladder calculi must be surgically collected.  Calculi that are not obtained surgically will be rejected.
Calclui should be sent to the microbiology laboratory in a sterile container.  A smal amount of sterile saline (e.g., 1-2 mL) may be added to the specimen to prevent drying.
Accurate patient identification must be made prior to sample collection.  Patient identification should be done in accordance with site policy.
Samples and requisitions must be labeled/completed in accordance with the Shared Health Specimen Acceptance Policy.
Collection Devices:
Specimen Required: Renal, Prostatic, or Bladder Calculi - Renal/bladder/prostatic calculi, no minimum volume but larger volume preferred. (Adult and Pediatric)
Reference Values:
A descriptive report will be sent.  The microbiology laboratory will culture for bacteria that are commonly implicated as a cause of urinary infections.  If Gram-negative bacilli, Corynebacterium urealyticum, and/or enterococci are recovered in any amount, they will be identified and susceptibility testing will be performed.  If other bacteria are recovered, they will be identified and listed.
For specimens from which no organisms are recovered, a report of "No organisms isolated."  will be issued by the microbiogy laboratory.
The anticipated turn-around-time is two to three days from receipt of the specimen in the microbiology laboratory.
See Also:
More Information:
Specimen Handling:
Local: Transport as soon as possible, hold at room temperature.
Courier/local storage: ≤24 hours at room temperature.  Ensure samples that are being sent to a referral laboratory are packaged in accordance with Transport of Dangerous Goods recommendations for diagnostic samples.