Page 1034 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

H aemolymphatic system 1009

VetBooks.ir 9.8 9.9

1 2 3 4 5 6 7 8 9 10 11 12
Fig. 9.8 Positive Coombs test with 1:64 titre
(negative <1:16). Test performed in a 96-well plate
with progressive dilutions of the sample. Well number Fig. 9.9 Technique used to transfer plasma from a
1 (far left well) is the negative control, well numbers microhaematocrit tube to a refractometer to measure
2–7 are positive (lattice formation, best observed plasma protein concentration.
in wells 5–7) and well numbers 8–12 are negative
(RBCs fall to the bottom of the well to form a pellet).

refractive index, producing a false elevated result. analysers. Individual proteins can be separated by
Serum protein is typically measured using the biu- serum protein electrophoresis for a more detailed
ret colourimetric assay on automated chemistry analysis of increased protein concentration.

DISORDERS OF THE HAEMOLYMPHATIC SYSTEM

ANAEMIA the accurate determination of the presence of a
regenerative response by most methods. Other
Anaemia is a decrease in the oxygen-carrying indicators of possible bone marrow erythro-
haemoglobin content of blood due to a decrease cytic hyperplasia include increased anisocyto-
in RBC concentration. Anaemia is usually fur- sis, macrocytosis and a larger RDW (Fig. 9.10).
ther characterised based on the ability of the bone However, these features can be observed in other
marrow to respond to the deficit by expanding
production of erythrocytes. In most species there
are several characteristic features in the CBC that 9.10
facilitate determination of the presence or absence
of a regenerative bone marrow response (Table 9.1).
The hallmark of erythrocyte regeneration is the
presence of increased numbers of polychromato-
philic RBCs or reticulocytes. In the horse, these
cells are not released in quantities sufficient for

Table 9.1 Parameters used to determine
regenerative anaemia in the horse
• Serial haemograms
• Increased mean corpuscular volume (MCV)
• Increased RBC distribution width (RDW) Fig. 9.10 Blood smear from a horse with regenerative
anaemia showing marked anisocytosis. Haematocrit
• Decreased mean corpuscular haemoglobin concentration
(MCHC) 0.09 l/l (9%) (reference interval: 0.28–0.44 l/l
• Bone marrow evaluation [28–44%]); RDW 38.5 (reference interval: 18–21)
(Wright’s stain).