Staffed by three technicians with a true interest and years of experience in veterinary haematology.

Each and every haematology includes a smear examination: fresh smears, perfect or not, are deeply appreciated!

The haematology laboratory takes part in a national quality assurance scheme (UK NEQAS) to ensure measurable accuracy in our results. We aim to generate, validate and report results on the day of receipt of the sample, and usually within hours.

This laboratory handles:

Blood from domestic and laboratory animal species, with the exception of primates

Bone marrow aspirates

Clotting studies – PT/APTT and D – dimers.

Exotic mammal, bird, reptile, amphibian and fish blood.

Fibrinogen (in large animals).

Clinical pathologists are involved in consulting, bone marrow examination and a wider interpretation of the completed test panels.


Further Information



Our D - Dimer method is not only clinically validated (J Small Anim. Prac. 2008 Jul; 49 (7):344-8) but unlike some methods is fully quantitative.




Bone Marrow Aspirates

In the first instance, if you are at all unsure whether this is the next step, then do contact the clinical pathologists here. We, the other clinicians in the University of Bristol and in Langford Veterinary Services are always ready to discuss haematology results and the processes involved in cancer staging before you take the samples.


Persistent non - regenerative anaemia
Persistent bicytopenia
Neutropenia or thrombocytopenia where there is no obvious cause after investigation
Abnormal cells in circulation that cannot be explained
Staging of neoplasia, especially of types which often metastasize to bone marrow
Persistent hypercalcaemia that is significant and unexplained
Testing for certain organisms such as Leishmania or FeLV

Although these are the most common reasons for examining bone marrow, we can sometimes gain some information on iron stores, regeneration of red cells in horses and FeLV status in cats. There are often sensitive ways of investigating these problems without resorting to bone marrow: please call us if in doubt.

Samples Needed

A haematology (EDTA and smear of venous blood) on the day of sampling are crucial to make sure that the fast, dynamic of supply from the marrow and the peripheral demand for the cells is understood and appreciated. Changes such as left shift and toxic change in neutrophils can completely alter the interpretation of a depleted marrow: equally, a non regenerative anaemia in the blood of an animal that has been anaemic for a week or more can help the clinical pathologist make a diagnosis of an immune mediated disease. The cost of the haematology is included in the cytology for just this reason.

Where the haematology illuminates the cytology, histopathology provides an exceptional and necessary view of the overall cellularity of the marrow, the behaviour of cells and the only chance of observing fibrosis, cytologically normal cells behaving aberrantly, megakaryocyte numbers and special stains for further discrimination. The three methods of examination are complementary and individually irreplaceable.

Common problems

No blood submitted, no smears submitted

EDTA marrow aspirate only submitted - degeneration in morphology is rapid, especially in hot weather. Post mortem samples must be taken immediately. Samples for PCR only (e.g. for FeLV provirus only) are likely to be more robust.

Marrow smears un-smeared - allowing marrow to trickle without smearing the slides makes the samples too dense to see the individual cells.

Formalin fumes affecting cytology staining - please do all you can to separate cytology slide and the marrow core sample. Separate plastic bags are a minimum. Allow cytology slides to dry before packing.

Core biopsy too small or of cortical bone only - white, dense samples are less likely to yield information. In some cases, attempts from more than one site may be needed.

Sampling Sites

This is very much a matter of personal preference. The iliac crest may be easy in large dogs, but many people prefer to sample from the humerus.