Difference between revisions of "Blood Sample Collection"

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Sample ageing also increasesthe likelihood of haemolysis. Samples submitted to the laboratory should arrive within 2 days. Delays often resultin cell deterioration and lysis, therefore submission of a fresh smear is advisable.
 
Sample ageing also increasesthe likelihood of haemolysis. Samples submitted to the laboratory should arrive within 2 days. Delays often resultin cell deterioration and lysis, therefore submission of a fresh smear is advisable.
  
References: Nation Wide Laboratories  
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References: [[/en.wikivet.net/NationWide Laboratories|NationWide Laboratories]]
  
 
=== Sample Type Required table ===
 
=== Sample Type Required table ===

Revision as of 18:48, 7 March 2022

Introduction

When collecting blood samples, fill tubes containing anticoagulant to the fill line and mix gently immediately after collection. Vacutainers can be used for large animal blood sample collection, and a needle and syringe for small animals. The jugular vein is the preferred collection site using a wide bore needle to prevent haemolysis of the blood from using excessive suction during collection. The cephalic and saphenous veins are alternative venipuncture sites. Ensure the venipuncture site is clean and swabbed, wear gloves and ensure you have adequate restraint prior to collecting a blood sample.

Always label your sample tubes with permanent marker immediately with the animal's details and the date and time of collection. Serum samples can be processed by allowing the blood to clot in an upright position and removing the serum from the tube prior to sending the sample for analysis to avoid haemolysis (bursting of the red blood cells into the serum) during transit. A more ideal method of serum separation is to centrifuge the sample -balance the centrifuge by adding a tube filled with the same volume of fluid in the opposite well in the centrifuge for safety.

Sampling

Anticoagulated blood is required for cell counts. If there are any visible clots, even small ones, the sample is discarded, as the WBC and platelet counts will be inaccurate. EDTA is the best anticoagulant to preserve cell detail but this does not provide such good cell morphology as a well prepared fresh smear. Heparin can be used but produces poor staining of cells. EDTA tubes should be completely filled to the level indicated. An excess of EDTA causes red cell shrinkage and decreased PCV. Overfilling may lead to clotting. Blood should be analysed within 2-3 hours or kept refrigerated. After 6-24 hours storage, RBCs swell leading to increased PCV and MCV with reduced mean corpuscular haemoglobin concentration (MCHC). Other red cell indices are not affected. Artefactual changes may result from excess suction on the syringe, over zealous agitation of the EDTA tube and high environmental temperatures, which can all cause haemolysis.

Sample ageing also increasesthe likelihood of haemolysis. Samples submitted to the laboratory should arrive within 2 days. Delays often resultin cell deterioration and lysis, therefore submission of a fresh smear is advisable.

References: NationWide Laboratories

Sample Type Required table

The following table is a guide to the sample type required for some specific laboratory tests - seek guidance from your processing laboratory for confirmation of sample requirements, which can vary depending on the equipment used to analyse the sample.

Test Required Sample Required Comments
Haematology EDTA Mix gently immediately after collection
Biochemistry Serum Centrifuge after permitting sufficient clotting time (min 2 hours)
Fibrinogen Citrate Mix gently immediately after collection
SAA Serum Needs to be processed quickly as the half life is very short
Electrolytes Heparin Mix gently immediately after collection
Glucose Fluoride oxalate Can use fresh whole blood if tested immediately
Insulin Serum Fasting sample required
Prothrombin clotting time Citrate A normal sample is required for comparison
Progesterone Serum
Oestrone Sulphate Serum
Testosterone Serum Request Testosterone before Inhibin for GCTs
IgG Serum Measurement techniques vary so check sample requirements
ACTH EDTA plasma