On this page, we have provided links to videos that clinical pathology faculty and trainees at Cornell University have created for educational purposes.
In this video, we demonstrate how to measure a packed cell volume and total protein in EDTA-anticoagulated blood. The total protein result is provided on our hemogram results and is measured with a refractometer. The latter determines refractive index, which is influenced by soluble particles in plasma, such as protein and other so-called non-protein solids, e.g. urea nitrogen, glucose.
Blood smear preparation
In this video, we demonstrate how to make a high-quality blood smear for blood smear examination.
Tips on making a blood smear
This video provides tips on how to make a high-quality blood smear, paying attention to items such as how quickly the smear is made, the angle of the spreader slide, and other aspects of the technique.
This video demonstrates an optimal method for staining blood and cytologic smears with a rapid or quick stains, with examples of over- and understained blood smears.
Blood smear examination: Part 1
A blood smear provides a wealth of information of what is going on in the animal. But you will only be able to identify and use this information if you have an optimally prepared blood smear and know how to examine the smear to detect abnormalities. In this first video of a 2-set series on how to examine a blood smear, we use a powerpoint-based lecture to outline the optimal preparation of a blood smear for examination. A brief description of how to approach blood smear examination is also provided as well as information on what you can glean from a blood smear (a lot!).
Blood smear examination: Part 2
In this second video of a 2-set series on how to examine a blood smear, we use a digital slide to demonstrate a consistent approach to examining a blood smear.
A wealth of data is provided with the hemogram. Here, we outline how to approach this data to figure out what is going wrong with the animal, i.e. to identify pathologic processes such as anemia, inflammation or leukemia. We use hemogram results from a dog to show this approach, which involves breaking down the data into components for ease of interpretation: Erythrogram, leukogram and thrombogram, followed by plasma appearance and total protein measurement by refractometer.
A primer on leukemia
Leukemias, which are one of the hematopoietic neoplasms, are complex and can be difficult to diagnose or to distinguish into sub-types. Determining what type of leukemia an animal has is important because the type of leukemia impacts treatment and prognosis. In this first of a two part series of videos, we provide definitions and a classification scheme for leukemias, separating the different types as to stage of maturation (acute versus chronic) and origin (myeloid versus lymphoid) and introduce the concept of the primary acute and chronic leukemias versus a secondary leukemia associated with lymphoma (often thought of as “solid” hematopoietic neoplasms in extramedullary tissue versus blood and bone marrow with the primary leukemias). We call the latter “lymphoma with a leukemic phase”. Hemogram results are our clue as to the presence of the leukemia and the results that tip us off as to the presence of a leukemia in a given patient are briefly summarized.
Tools for leukemia diagnosis
In this second of the two part series, the tools that we use for phenotyping leukemias or differentiating reactive from neoplastic conditions involving lymphocytes are outlined. These tools are:
- Clonality: Differentiating reactive from neoplastic conditions involving lymphocytes
- Phenotyping with antibodies (immunophenotyping) or cytochemical stains): Used for classifying leukemias and identifying cell lineage.