Additional Information:

1. Sample collection: Blood samples must be collected into the appropriate containers. Collection into evacuated containers has become the norm. Potassium EDTA is the anticoagulant for haematology. Lithium heparin is not suitable for this purpose, because it does not permit differential white cell counting. Samples for blood biochemistry testing can be collected into heparinised or plain tubes for either plasma or serum biochemistry respectively. Coagulation studies and the modified Clauss method of measurement the acute phase protein fibrinogen can only be carried out using sodium citrate containers.
2. Sample technique: Samples should be collected in an aseptic manner, so as to avoid inducing sepsis, local general, into an otherwise healthy horse. Collection should be sympathetic, otherwise you run the risk of creating the potentially misleading artefacts that result from adrenal induced neutrophilia and splenic contraction.
3. Timing of sampling: The timing of elective sampling should reflect the questions that are being asked. There is little point in taking post exercise samples or sampling within two or three hours of exercise, if the issue is whether muscle enzymes are within the normal resting range. Samples for elective testing are best collected pre-exercise, early in the morning or alternatively, late in the afternoon when exercise has been completed in the morning.
4. Sample handling: Misleading artefacts can also arise from poor sampling handling in the period between collection and evaluation in the laboratory. The use of an insulated lightproof container, a laboratory blood sample rack and in hot climates, an ordinary household cold pack, can yield rich dividends in terms of the accuracy and value of the information generated from the sampling. Labelling should be legible and thought should be given to timing of transfer for analysis.