How to Ship Veterinary Diagnostic Samples to a Reference Lab

Shipping a diagnostic sample isn't clerical busywork. How a sample is collected, labeled, packed, cooled, and documented decides whether the lab can run the test at all.

A good shipment protects three things at once: the people handling the package, the integrity of the specimen, and the speed of the result. A bad one leaks, warms up, freezes when it shouldn't, arrives without matching paperwork, or misses a testing cutoff - and the diagnostic value is gone before the sample reaches the bench.

Here is the practical workflow veterinary teams should follow when sending samples to a reference lab.

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Start With the Test Requirement, Not the Box

Before you pack anything, confirm the sample type, container, volume, temperature, and form the test requires.

Two tests on the same patient can need completely different handling. A chemistry panel, CBC, PCR, culture, fecal, cytology, urinalysis, biopsy, and endocrine test may each call for a different tube, temperature, or prep. Some specimens refrigerate, some freeze, some must never freeze, some need serum separated from cells, and others need whole blood in the correct anticoagulant tube.

Work in this order:

1. Identify the test being ordered.
2. Confirm the required specimen type.
3. Collect the sample in the correct container.
4. Label the primary container before packing.
5. Complete the submission form.
6. Package for the sample's classification and temperature.
7. Ship by a service that arrives during the lab's receiving hours.

When a test has special handling instructions, those override your general shipping habits. The test menu lists the specimen and handling requirement for each test.

Know the Shipping Classification

Veterinary diagnostic samples fall into three broad classes.

Exempt Animal Specimen

Most routine samples have a minimal chance of carrying a pathogen and can ship as Exempt Animal Specimen - as long as they are packed to prevent leakage in normal transit. "Exempt" does not mean loose in a bag or envelope: you still need protective packaging, clear labels, and enough absorbent material to contain a leak from the primary tube.

Biological Substance, Category B

Use Biological Substance, Category B when a sample is known or reasonably expected to contain a pathogen but does not meet the higher-risk Category A definition. These ship under UN3373 and require compliant triple packaging and markings.

Category A Infectious Substance

Category A covers infectious substances transported in a form capable of causing permanent disability, life-threatening disease, or fatal disease in otherwise healthy humans or animals. Routine submissions almost never qualify. But if you suspect a foreign animal disease, reportable disease, high-consequence pathogen, or a dangerous culture or isolate, do not ship it like routine work - contact the reference lab, your state veterinarian, or the appropriate regulatory authority first.

Use Triple Packaging

Triple packaging is the core structure for every diagnostic shipment.

• Primary receptacle - the tube, cup, vial, swab container, or biopsy jar holding the specimen. Leakproof for liquids, siftproof for solids, caps secure, not overfilled, and fragile containers separated so they cannot break against each other.
• Secondary packaging - the sealed inner layer around the primary container, usually a biohazard specimen bag or sealed canister. For liquids, place enough absorbent material between the primary and secondary to soak up the entire contents if the tube breaks.
• Outer packaging - the rigid or insulated shipping box that absorbs the crushing, vibration, pressure changes, and temperature swings of transit. A paper envelope, thin mailer, or unprotected bag is not acceptable.

The stack looks like this: primary container → absorbent and cushioning → sealed secondary container → rigid or insulated outer box → shipping label and required markings.

Label Every Sample Before It Leaves the Practice

Never let a sample rely on the submission form for its identity. Label every primary container with at least:

• Patient name or ID
• Owner last name or account identifier
• Species
• Sample type or source
• Collection date
• Practice name or submitting veterinarian, when space allows

For multi-sample cases, make sure each tube matches the form. If a case includes urine, serum, whole blood, feces, and swabs, every container has to be identifiable on its own. Unlabeled or mismatched samples delay accessioning, create uncertainty, or make the specimen unusable.

Keep Paperwork Dry and Separate

The submission form rides inside the outer box - but in its own sealed plastic bag, away from the specimens and cold packs, so condensation or a leak can't ruin it. Start from the submission forms and include:

• Practice name and contact information
• Veterinarian name
• Patient and owner information
• Species, breed, age, and sex
• Sample type and collection date
• Tests requested
• Relevant clinical history and current medications
• Billing or account information
• Any special handling notes

Clinical history matters. The lab cannot interpret a sample in a vacuum; the more precise the history, the faster the diagnostic team can pick the right workflow, recognize conflicts, and return useful results.

Protect the Cold Chain

Temperature control is one of the most common failure points in sample shipping.

Use cold packs, never loose ice or ice cubes - ice melts, leaks, and can destroy paperwork or compromise the outer box. Place cold packs outside the secondary container, not directly against sensitive specimens, unless the test instructions allow it.

Don't freeze whole blood unless the test specifically requires it; freezing damages cellular elements and makes hematology samples unsuitable. Serum and plasma vary - some tests need them chilled, others frozen after separation. Follow the specific test requirement.

Use dry ice only when a sample must stay frozen and your team is trained to ship with it. Dry ice is a regulated dangerous good: the package must vent carbon dioxide gas and be marked correctly. If the test doesn't require dry ice, a frozen shipment usually creates more problems than it solves.

Ship for Arrival, Not Just Departure

A package isn't successful because it left the practice. It's successful when it arrives at the lab in usable condition, during receiving hours.

For most perishable samples, overnight shipping is the safest default. Avoid Friday shipments, pre-holiday shipments, or anything that could sit in a warehouse over the weekend unless Saturday delivery and lab receiving have been confirmed.

Before handing off the box, confirm:

• The carrier will deliver to the lab's physical receiving address
• The package will arrive within receiving hours
• The label shows the correct service level
• The shipment is trackable
• Saturday delivery is available if it's needed
• There are no holiday closures or weather disruptions
• Temperature-sensitive material is accounted for

A one-day delay can turn a good sample into a compromised one. Practices outside the local area should review out-of-state shipping; local practices can often use courier pickup instead of shipping at all.

Match the Packaging to the Specimen

Whole Blood

Collect in the correct tube, fill to the proper level, invert gently when required, and keep it away from temperature extremes. Do not freeze unless a specific test says to. For hematology, include freshly prepared blood smears when requested.

Serum and Plasma

For most tests, separate serum or plasma from cells before shipping - leaving it on cells too long can skew results. Some tests need it chilled, others frozen after separation. Label transferred samples clearly so the lab knows what it received.

Urine

Use a leakproof container and handle it per the test requirement. Refrigeration often slows cellular deterioration and bacterial overgrowth, but the correct handling depends on the order. If culture is requested, collection method and timing matter.

Feces

Ship fresh, sealed, and clearly labeled, and don't overfill the container. Use the container or preservative the test requires - don't add formalin or anything else unless the test specifically calls for it.

Swabs

Submit in the correct transport medium for the test. A bacterial-culture swab isn't handled the same way as a PCR swab. Label the source clearly, especially when submitting multiple swabs from one patient.

Tissue and Biopsy

Fresh, fixed, and frozen tissue are not interchangeable. Package formalin-fixed samples so the container cannot leak, freeze, or contaminate other specimens. Fresh tissue may require refrigeration or freezing depending on the test.

When You're Using a B&L Shipping Label

Prepare the sample first, then create or print the label, and confirm it matches the package, destination, and service level the specimen needs. You can request a shipping label online.

Before pickup or drop-off, the package should contain:

• Properly labeled samples
• A completed submission form and any test-specific paperwork
• Absorbent material
• Sealed secondary packaging
• Cold packs or dry ice only when appropriate
• Required outer markings
• The correct shipping label
• A tracking number kept on file at the practice

Not sure which service level or temperature condition to use? Contact B&L before shipping. A short call beforehand beats a delayed or compromised result after arrival.

Common Mistakes That Delay Testing

Most failures are simple and preventable: samples arrive unlabeled, tubes leak, paperwork gets wet, the wrong tube is used, serum isn't separated, a cold sample arrives warm, whole blood freezes, the package arrives after the lab has closed, the test doesn't match the specimen, the sample is too small, or multiple patients are packed together without clear identification.

The fix is a repeatable practice workflow:

Collect → label → verify specimen type → complete form → seal primary → add absorbent → seal secondary → protect paperwork → add cold packs if required → mark package → ship overnight → save tracking.

Run it the same way every time and far fewer samples are compromised.

Final Pre-Shipment Checklist

Before the package leaves your practice, confirm:

• The correct test was selected
• The specimen type matches the test requirement
• Every primary container is labeled
• Containers are sealed and protected from breakage
• Absorbent material is included for liquids
• Samples are inside sealed secondary packaging
• Paperwork is complete and bagged separately
• The outer box is rigid and transport-ready
• The package is marked correctly for its classification
• Temperature-sensitive samples have the right cold pack or dry ice setup
• The carrier will deliver during lab receiving hours
• The tracking number is saved

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Need Help Sending Samples to B&L?

B&L Reference Laboratory works with veterinary practices to make diagnostic testing easier, from routine submissions to more specialized workflows. If you need to send samples, confirm specimen requirements, or ask about test handling, you can request a shipping label, view the test menu, or contact the B&L team before shipping.