TEST DIRECTORY... | MIDx Labs

URINE CULTURE WITH REFLEX TO ANTIMICROBIAL SUSCEPTIBILITY TESTING (UCX)

Identifies causative organisms in suspected urinary tract infection and determines antibiotic susceptibility to guide treatment.

LIS PANEL CODE: UCS0001

INDIVIDUAL LIS TEST CODES INCLUDED WITHIN PANEL: URINE CULTURE ROUTINE, ORG

CPT CODE: 87088

ALIASES: UCX, C&S, Aerobic Bacteria Culture, Urine

METHODOLOGIES: Bacterial Culture (Aerobic, Selective Media), with Reflex to Automated Organism Identification & AST if Growth is Present

Laboratory Developed Test (LDT): Performance characteristics determined by Michigan Innovative Diagnostics. This test has not been cleared or approved by the FDA.

SPECIMEN:

- Type: Clean-Catch Urine

- Container: Sterile Urine Container (Boric Acid preservative preferred if transport delay is anticipated)

- Minimum Volume Required: 3 mL

- Storage/Handling: Specimen should be collected using proper clean-catch technique to minimize contamination and transported to the laboratory promptly. If testing cannot be performed within the stability window below, refrigerate immediately.

- Stability:

Room Temperature (20-25 °C): 2 hours (1 day if collected in a Boric Acid preservative tube)

Refrigerated (2-8 °C): 1 day

Frozen (-20 °C or colder): Not Accepted

- Turnaround Time: 24 - 72 hours from receipt (final results dependent on culture growth and reflex to identification/susceptibility).

Special Instructions: Specimens with bacterial growth meeting clinically significant colony count thresholds (typically >= 10^5 CFU/mL of a single or predominant organism) will automatically reflex to organism identification and antimicrobial susceptibility testing, and any additional testing will be added to the original order.

Patients should be instructed to collect a clean-catch, midstream sample to minimize contamination from external flora, using the following procedure:

Wash hands thoroughly with soap and water before collection.
Cleanse the genital area from front to back using the provided antiseptic wipe(s):
- Females: Spread the labia and wipe from front to back on each side, then down the middle.
- Males: Retract the foreskin (if uncircumcised) and wipe the tip of the penis in a circular motion.
Begin urinating into the toilet, allowing the first portion of the stream to pass.
Without stopping the stream, collect a midstream sample directly into the sterile specimen container, avoiding contact between the container and skin.
Finish urinating into the toilet, then securely cap the specimen container.

REJECTION REASONS: QNS, Specimen Received in Non-Sterile/Incorrect Container, Stability Violation, Visibly Contaminated Specimen (e.g., mixed flora suggestive of improper collection), Unlabeled/Mislabeled Specimen, Leaking Container

EXPECTED FINDINGS:

Urine Culture (UCX): No Growth Detected

Antimicrobial Susceptibility Testing (AST): Susceptibility testing is performed on clinically significant isolates recovered in culture. Results are interpreted using current CLSI M100 breakpoints and reported with an interpretive category:

1. Susceptible (S): Isolate likely to be inhibited by the concentration of the agent normally achieved with the recommended dosage for the site of infection.

2. Intermediate (I): Isolate falls in a range where clinical response may be lower than for susceptible isolates. The agent may still be effective at sites where the drug is physiologically concentrated (e.g., urine) or when a higher dosage is used. Also serves as a buffer zone to prevent minor technical variation from causing major interpretive discrepancies.

3. Resistant (R): The isolate is not inhibited by normally achievable concentrations of the agent, or possesses a resistance mechanism associated with clinical failure.

4. Positive - ESBL Screen (POS): Presumptive extended-spectrum beta-lactamase producer.

5. Negative - ESBL Screen (NEG): Non-extended-spectrum beta-lactamase producer.

Agents are selected per organism and specimen source in accordance with CLSI-recommended guidelines. Agents with intrinsic resistance are suppressed. Interpretive categories reflect in vitro activity only; correlation with clinical presentation and site of infection is advised.