Urine
4.0 mL
Specimen Type
Clean-catch mid-stream urine (CCMS) or straight catheter collection.
Volume
Typically, 10 mL for the urinalysis tube and 4 mL for the gray-top culture tube, or as specified by the lab (fill to minimum line).
Handling
Transfer urine from the sterile cup into the appropriate tubes immediately after collection using a transfer device if available. The gray-top (boric acid) tube must be mixed well by inversion (8-10 times).
Storage/Transport
Unpreserved (Sterile Cup): Transport to the lab within 1 hour, or refrigerate at 2-8°C for up to 24 hours if delivery is delayed. Unrefrigerated samples older than 2 hours may yield inaccurate results.
Storage/Transport
Preserved (Gray-Top Tube): Can be transported at room temperature for up to 48 hours or refrigerated for up to 5 days (check lab-specific guidance).
Unacceptable Conditions
Quantity not sufficient (QNS) for analysis; frozen specimens; tubes with inappropriate preservatives (e.g., tartaric acid); urine collected from a drainage bag.
(RML)
Interference
Dilution: High fluid intake before collection can dilute the urine, potentially leading to false-negative results for leukocytes, nitrites, and bacteria. First-morning void is often preferred as it is more concentrated.
Contamination: Improper cleaning of the genital area or collecting a non-midstream sample can contaminate the specimen with external bacteria, leading to potentially misleading results, including the recovery of multiple organisms which may indicate contamination rather than true infection.
Medications: Inform the healthcare provider about any medications, especially antibiotics, as they can affect bacterial growth in culture and influence the interpretation of results.
Collection timing: Bacteria need sufficient time (at least 4 hours of bladder retention) to produce detectable levels of nitrites; collecting a sample with less retention time may lead to false-negative nitrite results.
Other substances: Vaginal lubricants, creams, or excessive use of antiseptic wipes/soaps just before collection may interfere with the test.
Miscellaneous Instruction to Collector
Patient Instruction: Provide clear, detailed instructions for a clean-catch mid-stream urine collection to minimize external contamination. Ensure the patient understands to clean the urethral area, void a small amount into the toilet, then collect the “”midstream”” portion in the sterile cup.
Safety: The collector should wear appropriate Personal Protective Equipment (PPE), such as gloves.
Labeling: Label all tubes/containers with the patient’s full name, date of birth, date, actual time of collection, and specimen type/source.
Transfer: When using a transfer device with a collection cup, ensure proper technique to fill the vacuum tubes without touching the inside of the cap or container. The collection cup itself is usually discarded after transfer and not sent to the lab.
Documentation: Document any relevant clinical information, such as the patient’s symptoms (dysuria, urgency, flank pain) or current antibiotic use, on the requisition form to aid in result interpretation.
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