Sample Collection and Submission Guidelines

Patient preparation

For most biochemical tests in dogs and cats, fasting for at least 8 hours is recommended whenever the patient's clinical condition allows. Water may remain available.

Fasting is not essential for emergency patients or routine haematology. If the patient has eaten shortly before sample collection, this should be noted on the Test Request Form.

Venepuncture

Use a needle of an appropriate gauge for the size of the patient and the vessel being sampled. Avoid prolonged venous stasis, repeated venepuncture and excessive suction, as these may contribute to haemolysis and affect some haematological parameters.

When several sample types are collected at the same time, use the recommended order of draw:

Tubes containing anticoagulant should be gently inverted several times immediately after collection. Do not shake.

Tube selection

The appropriate tube depends on the requested test. Detailed information on individual tube types is available on the Sampling Materials page.

If you are unsure which tube is required, please contact the laboratory before collecting the sample.

Minimum sample volume

Please provide the minimum volume specified for the requested test whenever possible.

For very small patients or when only a limited sample volume is available, contact the laboratory before submission. In many cases, the selection of tests can be adapted to the amount of sample available.

Serum separation

Allow blood collected for serum to clot fully before centrifugation, usually for approximately 20–30 minutes at room temperature.

Centrifuge at approximately 1700–2000 ×g for 10 minutes, or according to the recommendations of the tube and centrifuge manufacturer.

Relative centrifugal force (×g, RCF) is preferred to rpm when defining centrifugation conditions, as the corresponding rpm depends on the rotor radius.

After centrifugation, separate the serum from the cellular component as soon as possible, particularly if the sample will not be analysed immediately.

Haemolysis and lipaemia

Minimise haemolysis by using appropriate venepuncture technique, a suitable needle and gentle sample handling.

Marked haemolysis, lipaemia or icterus may interfere with some laboratory measurements. These changes are taken into account when sample quality and laboratory results are assessed.

Cystocentesis

Cystocentesis is the preferred collection method for urine culture, as it minimises contamination from microorganisms in the distal urinary and genital tracts.

Other collection methods are acceptable for routine urinalysis. The collection method must always be recorded on the Test Request Form, as it may affect interpretation of both urine sediment and microbiological findings.

If the sample cannot be submitted immediately, store it at 2–8°C. Submit promptly; sample stability and acceptable transport times depend on the investigation requested.

Free-catch urine

Free-catch urine is suitable for routine urinalysis. Whenever possible, collect a mid-stream sample into a clean container.

Because contamination from the distal urinary and genital tracts may occur, the collection method should always be considered when interpreting urine sediment and, particularly, bacterial culture results.

Catheterisation

Urine may be collected using a sterile urinary catheter when clinically appropriate.

The initial portion of urine may be discarded before collecting the sample. Record the collection method on the submission form, as catheterisation may affect interpretation of the findings.

Sample freshness

Submit the freshest possible faecal sample, particularly when testing for protozoa or other organisms for which morphology or motility may be important.

If the sample cannot be submitted immediately, keep it in a tightly closed container at 2–8°C, unless otherwise specified for the requested test.

Quantity and packaging

For most routine faecal examinations, submit approximately 5 g of faeces.

Place the sample in a clean, tightly closed faecal container. Avoid contamination with soil, litter, sand or other environmental material.

Faecal culture

For bacterial culture, provide the animal species, relevant clinical history, current or recent antimicrobial treatment and any suspected infectious agent, where applicable.

Submit promptly; sample stability and acceptable transport times depend on the investigation requested.

Fine-needle aspiration (FNA)

For most cytology samples, 21–25G needles are recommended. Needle gauge should be selected according to the type, location and consistency of the lesion.

Depending on the characteristics of the lesion, either an aspiration or non-aspiration (capillary) technique may be used.

Place the collected material onto at least 2–4 clean microscope slides and prepare the smears using minimal pressure to avoid cell damage.

Allow all slides to air-dry completely.

Impression smears

Gently blot excess blood or fluid from the surface of the lesion or tissue before pressing it lightly onto a clean microscope slide.

Impression smears are particularly useful for ulcerated or exudative lesions and for freshly cut tissue surfaces. Allow slides to air-dry completely.

Body fluids

For cytological examination of body fluids, where sufficient sample is available, submit:

• EDTA tube – for cell counts and cytological examination
• sterile plain tube without additives – when additional biochemical or microbiological testing may be required

Several direct smears should also be prepared immediately after collection, particularly for samples with low cellularity or when delayed transport is expected.

Transporting cytology slides

Slides must be completely air-dried before packaging and protected from breakage in a rigid microscope slide container.

Swabs with transport medium

Use a sterile swab with an appropriate transport medium.

Collect the sample from the site of active disease while avoiding contamination from surrounding tissues. Use a separate swab for each anatomical site.

Submit promptly; sample stability and acceptable transport times depend on the investigation requested.

Until transport, store the sample according to the requirements of the transport system being used.

Tissue, aspirates and fluids

For deep infections, aspirates, fluid samples or tissue are preferable to superficial swabs whenever possible.

Collect samples aseptically into a sterile, tightly closed container without preservative. Do not use formalin for microbiological samples.

Urine for culture

Cystocentesis is the preferred collection method for bacterial urine culture.

When cystocentesis is not possible, a urine sample collected by sterile catheterisation may be used. The collection method must always be documented to allow appropriate interpretation of the culture result.

Store the sample at 2–8°C until transport. Submit promptly; sample stability and acceptable transport times depend on the investigation requested.

Labelling tubes and containers

Every sample must be clearly labelled with at least:

• patient name or identification
• animal species
• sample type or anatomical site
• date of collection

The anatomical site is particularly important for cytology and microbiology samples.

Test Request Form

A completed Test Request Form should accompany every submission.

Please include the patient and veterinarian details, requested tests and all relevant clinical information.

Clinical information

Clinical information improves the interpretation of results. Useful information includes:

• duration and nature of clinical signs
• anatomical location of the lesion
• current treatment
• previous laboratory findings
• relevant differential diagnoses

Temperature

Transport requirements depend on the sample type and requested test:

• EDTA whole blood: refrigerate if prolonged transport is expected; do not freeze.
• Separated serum/plasma: generally store at 2–8°C; freezing may be required for selected tests.
• Cytology slides: dry, at room temperature and protected from moisture and formalin.
• Citrate samples for coagulation testing: submit promptly; sample stability and acceptable transport times depend on the investigation requested.
• Microbiology samples: storage conditions depend on the material and suspected microorganism.

Packaging

Samples must be securely closed and protected against leakage and breakage. Liquid samples should be placed in leak-proof secondary packaging with sufficient absorbent material.

Where applicable, biological samples sent by courier should be packaged in accordance with the requirements for UN 3373 – Biological Substance, Category B.

Arranging sample collection

VetPro organises sample transport throughout Serbia and regionally according to available routes and collection schedules. To arrange sample collection, use the VetPro Portal or contact us.