Hematology

Reticulocytes are immature, anucleate erythrocytes which are released from bone marrow into the blood in increased numbers as a response to anemia caused by hemolysis (destruction) or loss (hemorrhage) of erythrocytes in most species (horses are a notable exception). Identification of reticulocytes allows assessment of whether bone marrow is responding to an anemia (given sufficient […]

Cells of the erythroid line vary hugely within the animal kingdom, in terms of size, number, shape, lifespan, metabolism, and response to injury/anemia. The wide range of normal red blood cell appearance across the various species presents a challenge to the observer. Familiarity with the appearance of normal red blood cells of the species at

To determine the adequacy of the regenerative response in dogs and cats, absolute reticulocyte counts can be calculated. This is the method used at Cornell University for determining the adequacy of a regenerative response as it takes into account the severity of the anemia but does not make assumptions about a “normal” hematocrit or correction

Blood for hematologic testing must be collected into an anticoagulant, preferably EDTA (purple top tube).  Blood smears should be made at the time of collection to minimize storage-associated changes, which invariably occur. Venipuncture should be minimally traumatic to minimize platelet activation and should be done using a minimum of a 23G needle (21-22G is ideal

In this section, the following will be covered: Overview of anemia (see below) with examples of how indices and severity can help us identify the mechanism and cause of anemia. Assessment of regeneration Mechanisms of anemia Causes of anemia Anemia summary: Summary of the mechanisms and causes (not exhaustive) of anemia. Overview Definition Anemia is

Platelets (or thrombocytes) in mammals are anucleate cells that contain small pink-red granules. Shed into the blood from megakaryocytes in bone marrow, they are key players in the hemostatic process. Though most platelets are smaller than red cells, exceptions to this are not uncommon in cats and dogs. In this section, we will cover: Normal

Infections with organisms can be detected by examination of peripheral blood smears. Some are important as causes of disease in the host animal, while others are essentially non-pathogenic under most circumstances. Some infectious agents cause hematologic changes but are not identified on the blood smear. Infectious agents (or byproducts of their presence) can be seen

Red blood cell morphology is species-dependent. There are also changes that occur in red blood cells that can give us clues as to underlying diseases. Some of these changes can be pathologic in one context (or in one species) or physiologic in another. For example, small Heinz bodies are commonly seen in the blood of

The thrombogram includes all tests that evaluate platelets, including the following: Assessment of platelet numbers: Platelet count and estimate. Assessment of platelet size: Mean platelet volume. Platelet morphologic features: This does not have its own category in a hemogram, but a comment is added if abnormalities in platelet features are observed Platelet count Platelet counts

Total solids/protein This is measured by refractometer and actually measures refractive index versus total protein. It is used as an estimate for total protein (which are the constituents of plasma that have the most effect on the refractive index). This is used as a quick guide as to potential mechanisms for anemia (e.g. a low