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Urinary Catheter Urinalysis with Reflex to Culture

CAUTI, asymptomatic bacteria, pyuria

Test Codes

EPIC: LAB7083

Department

Microbiology

Instructions

• This test is restricted to inpatients with an indwelling urinary catheter either currently in use or within 96 hours after removal.
• This test is contraindicated for the following patient populations:
  • Less than 18 years of age
  • Neutropenia
  • Transplantation, (solid-organ, hematopoetic)
  • Currently Pregnant
  • Pending Urologic Procedure.
• After the test is ordered, place the two collection labels on the tubes as follows:
  • “UA Conical Tube” – yellow-top urinalysis tube
  • “Ur Gray CS” – gray-top boric acid preservative tube.
• Proper specimen collection is very important. Organisms normally present in the urethra and periurethral areas can overgrow the pathogenic organisms, thereby providing inaccurate or misleading results. 
• Urine held at room temperature can support the growth of contaminants as well as pathogenic organisms. Microorganisms can multiply significantly after two hours at room temperature if the urine is not placed into an appropriate transport media.
• For more information, please refer to Specimen Collection Manual: Urine for Culture.

Specimen Collection Criteria

Collect: 15 mL of urine from an indwelling catheter and placed into a sterile, screw-capped container.

• Immediately transfer 4-5 mL of urine to a Gray-top Boric Acid urine transport tube.
• For specimens with less than 3 mL of urine (pediatric patients, patients with oliguria/anuria or urine obtained during surgical procedures):
  • Do NOT transfer urine to the Gray-top Boric Acid urine transport tube.
  • Maintain the urine in the collection cup and keep refrigerated (2-8°C or 36-46°F).
  • Send immediately to the Microbiology Laboratory.

Physician Office/Draw Specimen Preparation

This test is only available for inpatients with an indwelling urinary catheter either currently in use or within 96 hours after removal.

Preparation for Courier Transport

Transport: Urine in a sterile collection container or Gray-top Boric Acid tube, refrigerated (2-8°C or 36-46°F).

Rejection Criteria

• Urine collected from the bag attached to the indwelling catheter.

• Foley catheter tips.

• Specimens in non-sterile or leaking containers.

• Multiple specimens (more than one in 24 hours).

• 24-hour or pooled specimens.

• Original specimens delayed in transport to the Laboratory (greater than 2 hours at room temperature (20-26°C or 68-78.8°F) or greater than 24 hours refrigerated in Gray-top Boric Acid tube (2-8°C or 36-46°F).

• Specimens with greater than 3 mL of urine sent in a sterile cup and received more than 2 hours after collection at room temperature (20-26°C or 68-78.8°F) or 24 hours at refrigeration temperature (2-8°C or 36-46°F).

Inpatient Specimen Preparation

All samples with more than 3 mL of urine must be transferred to the Gray-top Boric Acid tube. Sterile cups with more than 3 mL of urine will be rejected if received more than two hours after collection.

Deliver specimens to the Laboratory for processing immediately after collection. 

In-Lab Processing

The laboratory should receive two specimens per patient order. The Yellow-top UA tube should be forwarded to urinalysis for testing. The Gray-top boric acid preservative tube should be forwarded to microbiology for storage. Based upon select test results from the urinalysis, the Microbiology Department will be notified electronically to remove the Gray-top boric acid preservative tube from storage and proceed with the urine culture. Select criteria used for the reflex algorithm are as follows:

• Microscopic examination will only be performed when the urine color is not yellow, the urine is not clear, or an abnormal result is obtained on the “dipstick” for glucose, bilirubin, ketone, blood, protein, nitrite or leukocyte esterase.
• Urine culture will only be performed if the microscopic examination demonstrates greater than 10 WBCs per high-power field and less than 50 epithelial cells per low power field.

Storage

Specimen Stability for Testing: 

COLLECTION CONTAINER	CONDITION	VOLUME	STABILITY
Boric Acid Tube	Room Temperature   (20-26°C or 68-78.8°F)   Refrigerated   (2-8°C or 36-46°F)   Frozen   (-20°C/-4°F or below)	4-5 mL Optimal Unacceptable	48 hours
Sterile Cup	Room Temperature    (20-26°C or 68-78.8°F)   Refrigerated   (2-8°C or 36-46°F)   Frozen    (-20°C/-4°F or below)	All >3 mL <3 mL Unacceptable	<2 hours <2 hours 24 hours

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 4 days 

Laboratory

Dearborn Microbiology Laboratory
Taylor, Trenton and Wayne sent to Dearborn Microbiology Laboratory for testing.

Royal Oak Microbiology Laboratory
Farmington Hills, Grosse Pointe, and Troy sent to Royal Oak Microbiology Laboratory for testing. 

Performed

Sunday – Saturday, 24 hours a day.

• Preliminary results available within 24 hours.
• Cultures on non-invasive specimens (random, clean catch, Foley catheter) with no growth will be reported as final in 1 day.
• Cultures on invasive specimens (straight/suprapubic catheter, cystoscopic) with no growth will be reported as final in 2 days.
• Reports on positive specimens may require 2-3 days for final reports due to additional testing.
• Antimicrobial susceptibility testing is not done on every specimen Clinicians are encouraged to contact the applicable Clinical Microbiology Laboratory for more information and additional requests. See contact information below. 

Reference Range

No growth.

Test Methodology

Aerobic culture and antimicrobial susceptibility testing.

Interpretation

By report.

Clinical Utility

This reflex testing algorithm helps reduce the unnecessary identification and treatment of patients with asymptomatic catheter-associated bacteriuria. 

Reference

1. McCarter, Y.S., E.M. Burd, G.S. Hall, and M. Zervos. 2009. Cumitech 2C, Laboratory diagnosis of urinary tract infections. Coord. ed. S.E. Sharp. ASM Press. Washington, D.C.
   
2. Humphries RM, Dien Bard J. 2016. Point-Counterpoint: Reflex cultures reduce laboratory workload and improve antimicrobial stewardship in patients suspected of having urinary tract infections. J Clin Microbiol 54:254–258.

CPT Codes

87086, 87088.

Contacts

Last Updated

10/25/2023