How do we avoid swapping samples between two different patients?

Swaps are prevented at the source, not downstream. The most effective measure is to label the tube at the moment of collection, in front of the patient, with at least two unique identifiers, and never to prepare a batch of tubes to assign later. The same identifiers must appear identically on the tube, the request form and the record. A second cross-check before dispatch, ideally by someone other than the person who drew the sample, catches the few discrepancies that slip through. Legibility counts as much as accuracy: a correct but unreadable label is as good as missing.

Can a sample be refrigerated while it waits, or should it always stay at room temperature?

It depends on the matrix and the test, and there is no single rule. Many samples benefit from refrigeration to slow alteration, but some degrade in the cold or must not be frozen, while others require serum separation before storage. That is why the reference is always the lab manual, which states for each test the correct storage and the stability window. Noting the collection time next to the sample lets the lab judge whether the elapsed time is compatible with the requested analysis.

What information does the request form need to be genuinely useful?

Beyond the patient identifiers and the requested tests, the form should carry species, age, sex and reproductive status, the date and time of collection, and an essential history with the clinical suspicion and current treatments. This is not a formality: it guides the lab's interpretation, which reasons differently about a value depending on clinical context. An incomplete form forces phone calls, delays or rework, and sometimes leads the lab to reject the sample, requiring a fresh draw on an already stressed animal.

Why do some samples arrive haemolysed and how do we reduce it?

Haemolysis almost always begins in the pre-analytical phase: an unsuitable needle gauge, over-forceful aspiration, shaking the tube, delayed separation or improper storage. Because it alters several parameters, a heavily haemolysed sample can make exactly the tests you need unreliable. It is reduced by refining draw technique, using suitable materials, gently inverting tubes rather than shaking them, and respecting serum or plasma separation times. Logging when haemolysis recurs, and with which operators or materials, helps pinpoint the structural cause rather than blaming chance.

Clinic operations35 minLevel: IntermediateUpdated on August 20, 2026

Handling lab samples from collection to dispatch

Handling lab samples in a veterinary practice: correct collection, labelling, storage, cold chain and dispatch to an external lab without errors.

Audience: Veterinarians
Species: All species
Scope: Valid everywhere, Italy, European Union

What you need before you start

Il manuale del laboratorio di riferimento con requisiti di provetta, volume e temperatura
Un frigorifero dedicato ai campioni con termometro e registro delle temperature
Un modulo di richiesta esami standardizzato, cartaceo o digitale, sempre disponibile
Etichette e un sistema di identificazione univoca del paziente condiviso dal team

Most laboratory errors do not begin in the analyser but in the minutes before analysis: a swapped label, the wrong tube, a sample left in the warmth, a half-filled request form. This pre-analytical phase is invisible on the report, yet it decides how reliable that report is, because a precise result on a degraded sample is precisely useless and, worse, misleading. In a practice working under pressure the defence is not one person's memory but a written flow that anyone can follow the same way. This guide sets out a repeatable process from collection to dispatch: how to identify the patient uniquely, how to pick and handle the right tube, how to store each matrix within the cold chain, and how to deliver a traceable, correctly documented sample to the external lab.

Why the pre-analytical phase decides the report

A laboratory, in-house or external, can only measure what it receives. If the sample arrives haemolysed, clotted, in the wrong tube or swapped with another patient's, the analysis will still return a number, and that number will be used to decide treatment. This is the danger of the pre-analytical phase: it produces not an obvious error but a plausible, false result. Standardising it is not bureaucracy, it is the part of the work that protects all the rest.

Identity error: sample attributed to the wrong patient, the gravest error because it is invisible downstream.
Matrix error: tube with the wrong anticoagulant, or none, for the requested test.
Storage error: sample left at room temperature when it needed refrigeration, or frozen when it should not have been.
Timing error: delay between draw and serum or plasma separation that alters certain parameters.
Documentation error: an incomplete form forcing rework at the lab, or rejection of the sample.

Identifying patient and sample without ambiguity

Identification is where the most expensive risk concentrates, and it must be settled before touching the animal. The rule is to label the tube at the moment of collection, in front of the patient, not afterwards and not in another room. A label added from memory ten minutes later, perhaps onto one tube among many, is the perfect recipe for a mix-up.

At least two identifiers on the sample: patient name and a second unique item such as record number or date of birth.
Labelling at the time of collection, on the spot, with the tube held next to the patient.
Consistency between tube label, request form and record entry: the same identifiers everywhere.
Owner name linked but not used as the sole reference, because namesakes and multi-pet homes create confusion.
Legible handwriting or a printed label: a correct but unreadable identification counts as missing.

The flow from collection to dispatch

A written flow turns a sequence of individual gestures into a repeatable process that holds even on chaotic days. The steps below describe the backbone common to different matrices; the technical detail of each test stays with the lab.

Check test and requirements before the draw
Confirm in the manual which tube is needed, the minimum volume and any fasting or timing requirements. Preparing the right materials first avoids repeating a draw on an already stressed animal.
Label and draw with correct technique
Label the tube in front of the patient, then draw while minimising haemolysis and respecting the tube filling order when more than one is needed.
Mix and treat the sample at once
Gently invert anticoagulant tubes the number of times specified, without shaking. Where serum or plasma is needed, respect clotting times and centrifuge within the required window.
Prepare aliquots and accessory material
Separate serum or plasma when required, prepare slides or swabs according to the test, and confirm every container carries the same identifiers.
Store at the right temperature until dispatch
Place each sample in its required condition, refrigerated, room temperature or frozen, and note the collection time. Wrong storage here undoes everything that came before it.
Complete the form and log the shipment
Fill the request form with tests, patient data and relevant history, then log date, time and courier. A sample without a complete form is a sample at risk of rejection.

Storage and the cold chain

Every matrix has its own storage conditions, and getting them wrong is one of the most common errors because it looks like a detail. The table below summarises the most common general logic: these are method pointers, not absolute rules, and must always be checked against the stabilities the lab declares for the specific test.

Common storage logic by matrix. The binding requirements and stability windows are those in the lab manual.
Matrix	Typical storage	Main watch-out
Separated serum or plasma	Refrigerated, frozen for delayed shipping on advice	Separate within the required window to avoid alteration
Whole blood in EDTA	Refrigerated, usually not frozen	Analyse or send promptly, time alters morphology
Urine	Refrigerated short term	Delay at room temperature alters sediment and culture
Faeces for parasitology or culture	Refrigerated as advised	Suitable container and enough volume, no contamination
Slides and smears	Room temperature, protected	Do not chill near wet samples to avoid condensation
Microbiology swabs	Transport medium per protocol	Respect the maximum delivery times of the medium used

Traceability, dispatch and handling results

The flow does not end when the sample leaves the practice: it ends when the report has been read, communicated and filed in the record. A report that arrives and sits unseen in an inbox is a system failure just as much as a lost sample. Traceability closes the loop, from draw to clinical decision.

Log every sample sent with patient, tests requested, date, time and courier in one searchable list.
Define who checks for incoming reports and how often, so no result is left orphaned.
Flag critical values at once to whoever holds the case, without waiting for the routine communication round.
File the report in the record linked to the identifiers used at collection, so it can be found over time.
Periodically review samples rejected or reworked by the lab: they are the map of your flow's weak points.

A good laboratory does not compensate for a poor pre-analytical phase: at best it certifies it with a precise, wrong number.
A shared principle in laboratory quality management

Frequently asked questions

How do we avoid swapping samples between two different patients?: Swaps are prevented at the source, not downstream. The most effective measure is to label the tube at the moment of collection, in front of the patient, with at least two unique identifiers, and never to prepare a batch of tubes to assign later. The same identifiers must appear identically on the tube, the request form and the record. A second cross-check before dispatch, ideally by someone other than the person who drew the sample, catches the few discrepancies that slip through. Legibility counts as much as accuracy: a correct but unreadable label is as good as missing.
Can a sample be refrigerated while it waits, or should it always stay at room temperature?: It depends on the matrix and the test, and there is no single rule. Many samples benefit from refrigeration to slow alteration, but some degrade in the cold or must not be frozen, while others require serum separation before storage. That is why the reference is always the lab manual, which states for each test the correct storage and the stability window. Noting the collection time next to the sample lets the lab judge whether the elapsed time is compatible with the requested analysis.
What information does the request form need to be genuinely useful?: Beyond the patient identifiers and the requested tests, the form should carry species, age, sex and reproductive status, the date and time of collection, and an essential history with the clinical suspicion and current treatments. This is not a formality: it guides the lab's interpretation, which reasons differently about a value depending on clinical context. An incomplete form forces phone calls, delays or rework, and sometimes leads the lab to reject the sample, requiring a fresh draw on an already stressed animal.
Why do some samples arrive haemolysed and how do we reduce it?: Haemolysis almost always begins in the pre-analytical phase: an unsuitable needle gauge, over-forceful aspiration, shaking the tube, delayed separation or improper storage. Because it alters several parameters, a heavily haemolysed sample can make exactly the tests you need unreliable. It is reduced by refining draw technique, using suitable materials, gently inverting tubes rather than shaking them, and respecting serum or plasma separation times. Logging when haemolysis recurs, and with which operators or materials, helps pinpoint the structural cause rather than blaming chance.

What to do next

Treat the pre-analytical phase as the part of the work that protects all the rest: identify the patient with at least two unique items and label the tube in front of them, pick the right matrix, and respect the times and cold chain the lab specifies. Log every dispatch, assign someone to check incoming reports, and close the loop by filing the result in the record. A written, shared flow is worth more than one person's memory.