Culture, Urine, Routine

1. Disinfect the catheter port with 70% alcohol and allow it to dry.
2. Aspirate at least 5 mL of urine using a sterile needle and syringe.
3. Transfer the urine to a urine transport tube (Vacutainer® grey-top tube). This transport tube already contains a preservative that prevents rapid multiplication of bacteria during specimen transport. Bacterial multiplication could cause the colony count to be erroneously high. Stability is 48 hours at room temperature or refrigerated.

Note: Specimens collected from the collection bag are not suitable for analysis. Please refer to the Test Directory for more information.

When submitting <3 mL of urine, place the urine in a sterile container and ship refrigerated. DO NOT put less than 3 mL in a Vacutainer^® gray-top tube or Copan UriSponge.

Note: Do not send more than 3 mL of nonrefrigerated urine in a sterile container. Such specimens are unacceptable for routine bacterial culture.

A minimum of 16 hours of incubation is recommended before examination of culture media using traditional incubation methods, and cultures can be reported as “no growth” after 18 hours of incubation.¹  In accordance with CLIA and CAP requirements, Quest has validated reporting “no growth” at 14 to 16 hours when Copan WASPLab smart incubators are used, as they have equivalent growth at 14 to 16 hours to standard incubators at 16 to 18 hours. This enables Quest to provide the same quality results more quickly to clients. 

An injury in the urinary tract can account for such findings, which are referred to as sterile pyuria. Sterile pyuria is more common in catheterized patients and in patients with one of the following: 

• Vesicourethral reflex
• Interstitial cystitis
• Polycystic kidney
• Staghorn calculi and stones of smaller size
• Anatomic abnormalities
• Tumor resting on the bladder or ureter

For patients with a high WBC and a “no growth” result, it is important to look for microorganisms during urinalysis or examination of a gram stain (test code 497). If microorganisms are observed but not recovered from routine culture, it is appropriate to culture for anaerobes and more slowly growing organisms including fungi and mycobacteria, especially if the patient has a chronic urinary tract infection or anatomic abnormality.

More than one urine culture may be required to establish a diagnosis of urinary tract infection. Factors such as timing of specimen collection, excessive fluid intake, and contaminated midstream urine can affect culture results.

Reculturing after treatment to prove bacteriologic cure is not recommended. However, if symptoms do not resolve or if symptoms recur, a subsequent urine culture may be performed. Follow-up cultures may be appropriate for pregnant women and patients at high risk for renal damage, even when they are asymptomatic.

If appropriate, follow-up cultures are recommended at 1 to 2 weeks after completion of therapy.