Haematology and blood biochemistry in the horse: a guide to interpretation

Lab blood tests as diagnostic aids for equine ailments

source: Annalisa Barrelet and Sidney Ricketts
In Practice vol 24 no 6, June 2002
starts p318, 10 pages long

Lab tests of equine blood samples can be useful diagnostic aids for checking for different types of diseases, for management purposes (eg checking on foals and performance horses) and may be needed for insurers, or export purposes. It is important that horses should be as calm as possible since spurious haemoconcentration can occur if the horse is frightened, and that samples are analysed promptly before they deteriorate. Lab results have limitations, and should not replace a thorough clinical examination, but rather should supplement such an examination.

Red and white cell counts and haemoglobin levels can reveal different conditions, for example, low counts for red cells indicate anemia, while high white cell counts (leuocytosis) with neutrophilia indicate bacterial infections, and low white cell counts (leucopenia) with neutrophenia indicate viral infections. Anaemia usually occurs as a result of other conditions. Leucocytosis may be due to stress, and leucopenia as a result of exhaustion or shock.

Protein analyses can also give clues to a horse's condition, for example, low albumin production can indicate liver failure. Other biochemical tests include glucose tests for equine Cushing's disease, and creatinine tests to assess renal function.

Lab tests are now essential in equine practice, and they can save money by helping vets achieve a timely diagnosis.