5 Additional Special Specimen Procedures

Plan and prepare the collection

The reliability of a specialized specimen can depend on patient preparation, exact timing, preservation, and prompt transport—not only on choosing the right container. Requirements vary by test and laboratory. Before collection, check the current test-specific instructions and follow the laboratory’s procedure; do not assume one temperature, preservative, or collection method applies to every test.

Confirm the order and required specimen, container, volume, collection time, fasting or dietary instructions, and other restrictions. Explain the procedure in plain language and provide written instructions if collection will continue at home. Do not advise a patient to stop or change medication unless the responsible clinician has instructed them to do so.

Prepare the correct labeled container, required preservative, protective materials, and transport arrangements before collection. Confirm when and where the specimen must be delivered, especially if it must remain chilled or frozen.

Use the required patient identifiers and record the collection date and time. For a timed collection, document start and end times, relevant dose or meal times when required, and any collection problem. Match the specimen to its order before it leaves the collection area.

Follow the specific instructions for mixing, clotting, centrifugation, aliquoting, light protection, and temperature. Secure the lid, use leak-resistant secondary containment, and keep paperwork separate from the specimen container. Protect specimens from temperature extremes and delays.

Collect 24-hour urine

For a typical 24-hour urine collection, the patient empties the bladder at the start time and discards that first void, recording the time. The patient then collects all urine for the next 24 hours, including the first void at the same time on the following day. A missed void can make the result unreliable.

Keep the collection container closed and store it at the temperature specified by the test instructions; many 24-hour urine collections require refrigeration or a cool place. Return the container promptly and report the total collection time and volume when requested.

Some containers contain preservatives that may be caustic or otherwise hazardous. Warn the patient, keep the container out of children’s reach, and follow the laboratory’s instructions about whether to add urine directly or transfer it from a smaller clean container. Do not discard a supplied preservative or add another substance unless instructed.

If urine is spilled, a void is missed, or the collection period is incorrect, contact the ordering service or laboratory for direction. Do not silently submit an incomplete collection as complete.

Time blood samples and drug levels

Some tests require collection at a specified interval after a meal, medication dose, infusion, or other event; others require more than one sample at defined times. Record the actual collection time and the relevant event time, not just the scheduled time.

For a drug level, follow the test’s instructions. Some require a trough sample just before the next dose, but not every drug test uses trough timing. Do not delay, omit, or alter a dose to fit a collection time without direction from the responsible clinician.

For glucose testing, follow the specific order’s fasting or post-meal timing instructions. A fasting glucose commonly requires at least eight hours without calories; a post-meal sample is collected at the ordered interval. Record deviations, such as eating during a fast or collecting outside the requested time, and ask the laboratory or ordering clinician whether recollection is needed.

Preserve temperature- and light-sensitive specimens

Specimens may require room-temperature, refrigerated, chilled-on-ice, or frozen handling. These conditions are not interchangeable. Use the test directory to determine the required temperature and the permitted time before processing or delivery.

If a specimen needs ice, use a closed, leak-resistant secondary container to prevent meltwater from reaching the specimen. If freezing is required, use the specified freezing and shipping method; do not assume an ordinary freezer or an ice pack is adequate.

For example, Mayo Clinic Laboratories instructs that its plasma ammonia specimen be placed on ice immediately, processed promptly, and frozen within two hours. This requirement is specific to that test and laboratory, not a universal protocol for all blood specimens.

Some analytes also degrade in light. Use the specified amber container or another light-protective covering, and maintain the required temperature.

Handle problems and protect safety

Use standard precautions and appropriate personal protective equipment. Treat specimens as potentially infectious; avoid splashes and recapping needles. Do not handle broken or leaking containers without following the required spill procedure.

Handle additives carefully. Preservatives can be hazardous; do not touch, smell, or transfer them casually. Follow the container warning and local instructions, and use only the additive and container specified for the test.

Before dispatch, confirm the identifiers, container, volume, collection time, and any required preparation or preservation. A wrong tube, insufficient volume, missing timed portion, unprotected light-sensitive specimen, temperature excursion, or delay may require laboratory consultation or recollection.

If a problem occurs, document and report it. Examples include a missed urine void, incorrect timing, an unfasted patient when fasting was required, delayed separation, or a specimen left at the wrong temperature. Contact the laboratory promptly; do not guess at a corrective procedure or conceal the deviation.

Use special handling pathways when required. Chain-of-custody specimens need documented control and transfers under the applicable procedure. Suspected infectious specimens must be packaged and transported according to institutional biosafety and shipping requirements.

Reliable special-specimen collection depends on matching preparation, container, timing, preservation, and transport to the specific test. Give clear instructions, record actual times, preserve the specimen as directed, protect patients and staff from hazards, and promptly report collection or handling errors. If instructions conflict or are unclear, pause and contact the laboratory rather than improvising.

• chain-of-custody specimen