make Vet Answers my homepage

Blood Smears - Make Them A Routine Test in your Veterinary Practice!

Posted in Operations @ Apr 20th 2017 - By Dr Gerardo Poli, Director Animal Emergency Services
Blood Smears Make Them A Routine Test In Your Veterinary Practice V2

Blood smear evaluation is an often overlooked but a very important aspect for in-house haematology.

With the advancement in haematology analysers that can now detect reticulocytes and even band neutrophils, some practitioners are beginning to rely solely on the numerical data alone in evaluating the patient’s blood. The art of blood smear interpretation is on the decline. However, it is an extremely valuable skill that needs to be practiced and perfected and should be part of every in-house haematology.

What are the benefits of understanding blood smears?

  • Identifying of a regenerative response, looking for reticulocytes (polychromatophils)
  • Looking for the possible causes of an anaemia – eg. heinz bodies, infectious microorganisms
  • Looking for spherocytes which can indicate an immune mediated haemolytic anaemias
  • Confirming thromobocytopaenias, as frequently platelet clumping can be reported as a thromocytopaenia.
  • Assessment of the nature of a leukocytosis. High leucocyte counts do not always mean infection!! Neutrophilias can be caused by other things apart from infection, stress, corticosteroids, neoplastic leukaemias.
  • Normal leucocyte counts do not always mean the patient is ok, patients can have severe left shifts but normal leucocyte counts

Blood smear evaluation begins with becoming accomplished at producing great diagnostic smears – this of course takes practice. Poorly performed smears can be non-diagnostic and frustrating to assess for both yourself and an external pathologist.

A few tips on the technique:

  • Use a very small drop of blood, if you have picked up too much blood with the ‘spreader’ slide, then lift off and start the smear away from that drop of blood
  • Angle the ‘spreader’ slide about 30 degrees. The bigger the angle, the shorter your smear.
  • The smear should end at about half to 3/4 of the way down the slide and must have a ‘feathered edge’.

Any questions for Gerardo? Ask them in the Comments section below.

This post originally appeared on Dr Poli's Blog on the 'miniVET guide Companion Animal Medicine' website and has been reproduced with full permission.

About Gerardo

Dr Gerardo Poli is an emergency and critical care veterinarian and company Director at Animal Emergency Services.  He has a strong focus in the triage, stabilisation and management of critically ill patients, small animal ultrasound and radiology and emergency surgery.

He is the author of The Mini Vet Guide To Companion Animal Medicine; a pocket sized, quick-reference guide designed to help veterinary students through their final years of vet school and also for recently graduated veterinarian making the transition into vet clinical practice. 

Find out more about The MiniVet Guide to Companion Animal Medicine by visitng the website:

Or visit the Facebook Page:

You can also find out more about the Animal Emergency Service in Brisbane here:


There are currently no comments.

Add Your Comments

All comments will be submitted to the administrator for approval.

To prevent spam, please type in the code found in the red box to verify you are a real person.
  Required fields

Blog Categories


Recent Blog Entries


Tag Cloud

follow us on twitter